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What is a Literature Review? How to Write It (with Examples)

A literature review is a critical analysis and synthesis of existing research on a particular topic. It provides an overview of the current state of knowledge, identifies gaps, and highlights key findings in the literature. 1 The purpose of a literature review is to situate your own research within the context of existing scholarship, demonstrating your understanding of the topic and showing how your work contributes to the ongoing conversation in the field. Learning how to write a literature review is a critical tool for successful research. Your ability to summarize and synthesize prior research pertaining to a certain topic demonstrates your grasp on the topic of study, and assists in the learning process. 

Table of Contents

• What is the purpose of literature review? 
• a. Habitat Loss and Species Extinction: 
• b. Range Shifts and Phenological Changes: 
• c. Ocean Acidification and Coral Reefs: 
• d. Adaptive Strategies and Conservation Efforts: 
• How to write a good literature review 
• Choose a Topic and Define the Research Question: 
• Decide on the Scope of Your Review: 
• Select Databases for Searches: 
• Conduct Searches and Keep Track: 
• Review the Literature: 
• Organize and Write Your Literature Review: 
• Frequently asked questions 

What is a literature review?

A well-conducted literature review demonstrates the researcher’s familiarity with the existing literature, establishes the context for their own research, and contributes to scholarly conversations on the topic. One of the purposes of a literature review is also to help researchers avoid duplicating previous work and ensure that their research is informed by and builds upon the existing body of knowledge.

What is the purpose of literature review?

A literature review serves several important purposes within academic and research contexts. Here are some key objectives and functions of a literature review: 2  

• Contextualizing the Research Problem: The literature review provides a background and context for the research problem under investigation. It helps to situate the study within the existing body of knowledge. 
• Identifying Gaps in Knowledge: By identifying gaps, contradictions, or areas requiring further research, the researcher can shape the research question and justify the significance of the study. This is crucial for ensuring that the new research contributes something novel to the field. 
• Understanding Theoretical and Conceptual Frameworks: Literature reviews help researchers gain an understanding of the theoretical and conceptual frameworks used in previous studies. This aids in the development of a theoretical framework for the current research. 
• Providing Methodological Insights: Another purpose of literature reviews is that it allows researchers to learn about the methodologies employed in previous studies. This can help in choosing appropriate research methods for the current study and avoiding pitfalls that others may have encountered. 
• Establishing Credibility: A well-conducted literature review demonstrates the researcher’s familiarity with existing scholarship, establishing their credibility and expertise in the field. It also helps in building a solid foundation for the new research. 
• Informing Hypotheses or Research Questions: The literature review guides the formulation of hypotheses or research questions by highlighting relevant findings and areas of uncertainty in existing literature. 

Literature review example

Let’s delve deeper with a literature review example: Let’s say your literature review is about the impact of climate change on biodiversity. You might format your literature review into sections such as the effects of climate change on habitat loss and species extinction, phenological changes, and marine biodiversity. Each section would then summarize and analyze relevant studies in those areas, highlighting key findings and identifying gaps in the research. The review would conclude by emphasizing the need for further research on specific aspects of the relationship between climate change and biodiversity. The following literature review template provides a glimpse into the recommended literature review structure and content, demonstrating how research findings are organized around specific themes within a broader topic. 

Literature Review on Climate Change Impacts on Biodiversity:

Climate change is a global phenomenon with far-reaching consequences, including significant impacts on biodiversity. This literature review synthesizes key findings from various studies: 

a. Habitat Loss and Species Extinction:

Climate change-induced alterations in temperature and precipitation patterns contribute to habitat loss, affecting numerous species (Thomas et al., 2004). The review discusses how these changes increase the risk of extinction, particularly for species with specific habitat requirements. 

b. Range Shifts and Phenological Changes:

Observations of range shifts and changes in the timing of biological events (phenology) are documented in response to changing climatic conditions (Parmesan & Yohe, 2003). These shifts affect ecosystems and may lead to mismatches between species and their resources. 

c. Ocean Acidification and Coral Reefs:

The review explores the impact of climate change on marine biodiversity, emphasizing ocean acidification’s threat to coral reefs (Hoegh-Guldberg et al., 2007). Changes in pH levels negatively affect coral calcification, disrupting the delicate balance of marine ecosystems. 

d. Adaptive Strategies and Conservation Efforts:

Recognizing the urgency of the situation, the literature review discusses various adaptive strategies adopted by species and conservation efforts aimed at mitigating the impacts of climate change on biodiversity (Hannah et al., 2007). It emphasizes the importance of interdisciplinary approaches for effective conservation planning. 

How to write a good literature review

Writing a literature review involves summarizing and synthesizing existing research on a particular topic. A good literature review format should include the following elements. 

Introduction: The introduction sets the stage for your literature review, providing context and introducing the main focus of your review. 

• Opening Statement: Begin with a general statement about the broader topic and its significance in the field. 
• Scope and Purpose: Clearly define the scope of your literature review. Explain the specific research question or objective you aim to address. 
• Organizational Framework: Briefly outline the structure of your literature review, indicating how you will categorize and discuss the existing research. 
• Significance of the Study: Highlight why your literature review is important and how it contributes to the understanding of the chosen topic. 
• Thesis Statement: Conclude the introduction with a concise thesis statement that outlines the main argument or perspective you will develop in the body of the literature review. 

Body: The body of the literature review is where you provide a comprehensive analysis of existing literature, grouping studies based on themes, methodologies, or other relevant criteria. 

• Organize by Theme or Concept: Group studies that share common themes, concepts, or methodologies. Discuss each theme or concept in detail, summarizing key findings and identifying gaps or areas of disagreement. 
• Critical Analysis: Evaluate the strengths and weaknesses of each study. Discuss the methodologies used, the quality of evidence, and the overall contribution of each work to the understanding of the topic. 
• Synthesis of Findings: Synthesize the information from different studies to highlight trends, patterns, or areas of consensus in the literature. 
• Identification of Gaps: Discuss any gaps or limitations in the existing research and explain how your review contributes to filling these gaps. 
• Transition between Sections: Provide smooth transitions between different themes or concepts to maintain the flow of your literature review. 

Conclusion: The conclusion of your literature review should summarize the main findings, highlight the contributions of the review, and suggest avenues for future research. 

• Summary of Key Findings: Recap the main findings from the literature and restate how they contribute to your research question or objective. 
• Contributions to the Field: Discuss the overall contribution of your literature review to the existing knowledge in the field. 
• Implications and Applications: Explore the practical implications of the findings and suggest how they might impact future research or practice. 
• Recommendations for Future Research: Identify areas that require further investigation and propose potential directions for future research in the field. 
• Final Thoughts: Conclude with a final reflection on the importance of your literature review and its relevance to the broader academic community. 

Conducting a literature review

Conducting a literature review is an essential step in research that involves reviewing and analyzing existing literature on a specific topic. It’s important to know how to do a literature review effectively, so here are the steps to follow: 1  

Choose a Topic and Define the Research Question:

• Select a topic that is relevant to your field of study. 
• Clearly define your research question or objective. Determine what specific aspect of the topic do you want to explore? 

Decide on the Scope of Your Review:

• Determine the timeframe for your literature review. Are you focusing on recent developments, or do you want a historical overview? 
• Consider the geographical scope. Is your review global, or are you focusing on a specific region? 
• Define the inclusion and exclusion criteria. What types of sources will you include? Are there specific types of studies or publications you will exclude? 

Select Databases for Searches:

• Identify relevant databases for your field. Examples include PubMed, IEEE Xplore, Scopus, Web of Science, and Google Scholar. 
• Consider searching in library catalogs, institutional repositories, and specialized databases related to your topic. 

Conduct Searches and Keep Track:

• Develop a systematic search strategy using keywords, Boolean operators (AND, OR, NOT), and other search techniques. 
• Record and document your search strategy for transparency and replicability. 
• Keep track of the articles, including publication details, abstracts, and links. Use citation management tools like EndNote, Zotero, or Mendeley to organize your references. 

Review the Literature:

• Evaluate the relevance and quality of each source. Consider the methodology, sample size, and results of studies. 
• Organize the literature by themes or key concepts. Identify patterns, trends, and gaps in the existing research. 
• Summarize key findings and arguments from each source. Compare and contrast different perspectives. 
• Identify areas where there is a consensus in the literature and where there are conflicting opinions. 
• Provide critical analysis and synthesis of the literature. What are the strengths and weaknesses of existing research? 

Organize and Write Your Literature Review:

• Literature review outline should be based on themes, chronological order, or methodological approaches. 
• Write a clear and coherent narrative that synthesizes the information gathered. 
• Use proper citations for each source and ensure consistency in your citation style (APA, MLA, Chicago, etc.). 
• Conclude your literature review by summarizing key findings, identifying gaps, and suggesting areas for future research. 

The literature review sample and detailed advice on writing and conducting a review will help you produce a well-structured report. But remember that a literature review is an ongoing process, and it may be necessary to revisit and update it as your research progresses. 

Frequently asked questions

A literature review is a critical and comprehensive analysis of existing literature (published and unpublished works) on a specific topic or research question and provides a synthesis of the current state of knowledge in a particular field. A well-conducted literature review is crucial for researchers to build upon existing knowledge, avoid duplication of efforts, and contribute to the advancement of their field. It also helps researchers situate their work within a broader context and facilitates the development of a sound theoretical and conceptual framework for their studies.

Literature review is a crucial component of research writing, providing a solid background for a research paper’s investigation. The aim is to keep professionals up to date by providing an understanding of ongoing developments within a specific field, including research methods, and experimental techniques used in that field, and present that knowledge in the form of a written report. Also, the depth and breadth of the literature review emphasizes the credibility of the scholar in his or her field.  

Before writing a literature review, it’s essential to undertake several preparatory steps to ensure that your review is well-researched, organized, and focused. This includes choosing a topic of general interest to you and doing exploratory research on that topic, writing an annotated bibliography, and noting major points, especially those that relate to the position you have taken on the topic. 

Literature reviews and academic research papers are essential components of scholarly work but serve different purposes within the academic realm. 3 A literature review aims to provide a foundation for understanding the current state of research on a particular topic, identify gaps or controversies, and lay the groundwork for future research. Therefore, it draws heavily from existing academic sources, including books, journal articles, and other scholarly publications. In contrast, an academic research paper aims to present new knowledge, contribute to the academic discourse, and advance the understanding of a specific research question. Therefore, it involves a mix of existing literature (in the introduction and literature review sections) and original data or findings obtained through research methods. 

Literature reviews are essential components of academic and research papers, and various strategies can be employed to conduct them effectively. If you want to know how to write a literature review for a research paper, here are four common approaches that are often used by researchers.  Chronological Review: This strategy involves organizing the literature based on the chronological order of publication. It helps to trace the development of a topic over time, showing how ideas, theories, and research have evolved.  Thematic Review: Thematic reviews focus on identifying and analyzing themes or topics that cut across different studies. Instead of organizing the literature chronologically, it is grouped by key themes or concepts, allowing for a comprehensive exploration of various aspects of the topic.  Methodological Review: This strategy involves organizing the literature based on the research methods employed in different studies. It helps to highlight the strengths and weaknesses of various methodologies and allows the reader to evaluate the reliability and validity of the research findings.  Theoretical Review: A theoretical review examines the literature based on the theoretical frameworks used in different studies. This approach helps to identify the key theories that have been applied to the topic and assess their contributions to the understanding of the subject.  It’s important to note that these strategies are not mutually exclusive, and a literature review may combine elements of more than one approach. The choice of strategy depends on the research question, the nature of the literature available, and the goals of the review. Additionally, other strategies, such as integrative reviews or systematic reviews, may be employed depending on the specific requirements of the research.

The literature review format can vary depending on the specific publication guidelines. However, there are some common elements and structures that are often followed. Here is a general guideline for the format of a literature review:  Introduction:   Provide an overview of the topic.  Define the scope and purpose of the literature review.  State the research question or objective.  Body:   Organize the literature by themes, concepts, or chronology.  Critically analyze and evaluate each source.  Discuss the strengths and weaknesses of the studies.  Highlight any methodological limitations or biases.  Identify patterns, connections, or contradictions in the existing research.  Conclusion:   Summarize the key points discussed in the literature review.  Highlight the research gap.  Address the research question or objective stated in the introduction.  Highlight the contributions of the review and suggest directions for future research.

Both annotated bibliographies and literature reviews involve the examination of scholarly sources. While annotated bibliographies focus on individual sources with brief annotations, literature reviews provide a more in-depth, integrated, and comprehensive analysis of existing literature on a specific topic. The key differences are as follows: 

References 

• Denney, A. S., & Tewksbury, R. (2013). How to write a literature review.  Journal of criminal justice education ,  24 (2), 218-234. 
• Pan, M. L. (2016).  Preparing literature reviews: Qualitative and quantitative approaches . Taylor & Francis. 
• Cantero, C. (2019). How to write a literature review.  San José State University Writing Center . 

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Writing a Literature Review

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A literature review is a document or section of a document that collects key sources on a topic and discusses those sources in conversation with each other (also called synthesis ). The lit review is an important genre in many disciplines, not just literature (i.e., the study of works of literature such as novels and plays). When we say “literature review” or refer to “the literature,” we are talking about the research ( scholarship ) in a given field. You will often see the terms “the research,” “the scholarship,” and “the literature” used mostly interchangeably.

Where, when, and why would I write a lit review?

There are a number of different situations where you might write a literature review, each with slightly different expectations; different disciplines, too, have field-specific expectations for what a literature review is and does. For instance, in the humanities, authors might include more overt argumentation and interpretation of source material in their literature reviews, whereas in the sciences, authors are more likely to report study designs and results in their literature reviews; these differences reflect these disciplines’ purposes and conventions in scholarship. You should always look at examples from your own discipline and talk to professors or mentors in your field to be sure you understand your discipline’s conventions, for literature reviews as well as for any other genre.

A literature review can be a part of a research paper or scholarly article, usually falling after the introduction and before the research methods sections. In these cases, the lit review just needs to cover scholarship that is important to the issue you are writing about; sometimes it will also cover key sources that informed your research methodology.

Lit reviews can also be standalone pieces, either as assignments in a class or as publications. In a class, a lit review may be assigned to help students familiarize themselves with a topic and with scholarship in their field, get an idea of the other researchers working on the topic they’re interested in, find gaps in existing research in order to propose new projects, and/or develop a theoretical framework and methodology for later research. As a publication, a lit review usually is meant to help make other scholars’ lives easier by collecting and summarizing, synthesizing, and analyzing existing research on a topic. This can be especially helpful for students or scholars getting into a new research area, or for directing an entire community of scholars toward questions that have not yet been answered.

What are the parts of a lit review?

Most lit reviews use a basic introduction-body-conclusion structure; if your lit review is part of a larger paper, the introduction and conclusion pieces may be just a few sentences while you focus most of your attention on the body. If your lit review is a standalone piece, the introduction and conclusion take up more space and give you a place to discuss your goals, research methods, and conclusions separately from where you discuss the literature itself.

Introduction:

• An introductory paragraph that explains what your working topic and thesis is
• A forecast of key topics or texts that will appear in the review
• Potentially, a description of how you found sources and how you analyzed them for inclusion and discussion in the review (more often found in published, standalone literature reviews than in lit review sections in an article or research paper)
• Summarize and synthesize: Give an overview of the main points of each source and combine them into a coherent whole
• Analyze and interpret: Don’t just paraphrase other researchers – add your own interpretations where possible, discussing the significance of findings in relation to the literature as a whole
• Critically Evaluate: Mention the strengths and weaknesses of your sources
• Write in well-structured paragraphs: Use transition words and topic sentence to draw connections, comparisons, and contrasts.

Conclusion:

• Summarize the key findings you have taken from the literature and emphasize their significance
• Connect it back to your primary research question

How should I organize my lit review?

Lit reviews can take many different organizational patterns depending on what you are trying to accomplish with the review. Here are some examples:

• Chronological : The simplest approach is to trace the development of the topic over time, which helps familiarize the audience with the topic (for instance if you are introducing something that is not commonly known in your field). If you choose this strategy, be careful to avoid simply listing and summarizing sources in order. Try to analyze the patterns, turning points, and key debates that have shaped the direction of the field. Give your interpretation of how and why certain developments occurred (as mentioned previously, this may not be appropriate in your discipline — check with a teacher or mentor if you’re unsure).
• Thematic : If you have found some recurring central themes that you will continue working with throughout your piece, you can organize your literature review into subsections that address different aspects of the topic. For example, if you are reviewing literature about women and religion, key themes can include the role of women in churches and the religious attitude towards women.
• Qualitative versus quantitative research
• Empirical versus theoretical scholarship
• Divide the research by sociological, historical, or cultural sources
• Theoretical : In many humanities articles, the literature review is the foundation for the theoretical framework. You can use it to discuss various theories, models, and definitions of key concepts. You can argue for the relevance of a specific theoretical approach or combine various theorical concepts to create a framework for your research.

What are some strategies or tips I can use while writing my lit review?

Any lit review is only as good as the research it discusses; make sure your sources are well-chosen and your research is thorough. Don’t be afraid to do more research if you discover a new thread as you’re writing. More info on the research process is available in our "Conducting Research" resources .

As you’re doing your research, create an annotated bibliography ( see our page on the this type of document ). Much of the information used in an annotated bibliography can be used also in a literature review, so you’ll be not only partially drafting your lit review as you research, but also developing your sense of the larger conversation going on among scholars, professionals, and any other stakeholders in your topic.

Usually you will need to synthesize research rather than just summarizing it. This means drawing connections between sources to create a picture of the scholarly conversation on a topic over time. Many student writers struggle to synthesize because they feel they don’t have anything to add to the scholars they are citing; here are some strategies to help you:

• It often helps to remember that the point of these kinds of syntheses is to show your readers how you understand your research, to help them read the rest of your paper.
• Writing teachers often say synthesis is like hosting a dinner party: imagine all your sources are together in a room, discussing your topic. What are they saying to each other?
• Look at the in-text citations in each paragraph. Are you citing just one source for each paragraph? This usually indicates summary only. When you have multiple sources cited in a paragraph, you are more likely to be synthesizing them (not always, but often
• Read more about synthesis here.

The most interesting literature reviews are often written as arguments (again, as mentioned at the beginning of the page, this is discipline-specific and doesn’t work for all situations). Often, the literature review is where you can establish your research as filling a particular gap or as relevant in a particular way. You have some chance to do this in your introduction in an article, but the literature review section gives a more extended opportunity to establish the conversation in the way you would like your readers to see it. You can choose the intellectual lineage you would like to be part of and whose definitions matter most to your thinking (mostly humanities-specific, but this goes for sciences as well). In addressing these points, you argue for your place in the conversation, which tends to make the lit review more compelling than a simple reporting of other sources.

DEAN’S BOOK w/ Prof. CONNIE GRIFFIN

Honors291g-cdg’s blog.

How to Write a Literature Review

What is a literature review? Written in essay style, a literature review (Lit Review) describes, classifies, and evaluates the sources of information published on a given topic. A Lit Review is not just a list of books/articles.  It’s a review of a collection of research published by accredited scholars and researchers that is relevant to a research question. “Non-scholarly” sources, i.e., those you don’t want to reference, include but are not limited to magazines, newspapers, web sites, and non-published material. The Lit Review does not have to be exhaustive; the objective is not to list as many relevant books, articles, and reports as possible. The idea of the Lit Review is not to provide a summary of all the published work that relates to your research, but a survey (summary and evaluation) of the most relevant and significant work. A Lit Review is a critical look at the existing research that is significant to the work you are carrying out. It’s not just a summary. While you do need to summarize your relevant research, you must also: •    evaluate this work, •    show the relationships between different works, and •    demonstrate how it relates to your work. A Lit Review is about the existing literature on your subject and provides background for your own research findings or commentary. How much sense does your research make if you don’t provide background to the reader about past research conducted by others?

What is the value of a literature review? A Lit Review provides your reader with a survey of the professional publications available on your topic. It demonstrates that you have not only thoroughly researched your topic but also carefully examined and critically evaluated the range of relevant sources. In writing the Lit Review, your purpose is to convey to your reader what knowledge and ideas have been established on a topic and what their strengths and weaknesses are. A Lit Review: •  places the paper within the context of known research on the subject; focuses one’s own research topic. •  provides thorough knowledge of previous studies; introduces seminal works. •  indicates timely nature of one’s research, if applicable. •  suggests previously unused or underused methodologies, designs, quantitative, and qualitative strategies. •  identifies gaps in previous studies; identifies flawed methodologies and/or theoretical approaches; avoids replication of mistakes. •  identifies possible trends or patterns in the literature. •  helps the researcher avoid repetition of earlier research. •  determines whether past studies agree or disagree; identifies controversy in the literature. •  tests assumptions; may help counter preconceived ideas and remove unconscious bias.

What is the “literature” in a literature review? The “literature” is the collection of books and journal articles, government documents, and other scholarly works you found to be relevant to your research topic. •    Journal articles: An excellent source for a Lit Review. These are good especially for up-to-date information. They are frequently used in Lit Reviews because they offer a relatively concise, up-to-date format for research, and because all reputable journals are refereed or peer-reviewed, i.e., editors publish only the most relevant and reliable research that has been reviewed by other experts in the field. •    Books:  Generally, a good source for a Lit Review. Books tend to be less up-to-date as it takes longer for a book to be published than for a journal article. Textbooks are unlikely to be useful for including in your Lit Review as they are intended for teaching, not for research, but they do offer a good starting point from which to find better, more detailed sources. •    Conference proceedings: A good source for a Lit Review. These can be useful in providing the latest research or research that has not been published. They are also helpful in providing information on which people are currently involved in which research areas, and so can be helpful in tracking down other work by the same researchers. •    Government/corporate reports: A good source for a Lit Review. Many government departments and corporations commission or carry out research. Their published findings can provide a useful source of information, depending on your field of study. •    Newspapers: Not a good source for a Lit Review. Since newspapers are generally intended for a general (not specialized) audience, the information they provide will be of no use for your Lit Review. Journalists are generally not scholars, i.e., experts on the topic on which they are writing, and thus newspaper articles are not scholarly sources. •    Theses and dissertations: Can be a good source for a Lit Review. These can be useful sources of information. However there are disadvantages: 1) they can be difficult to obtain since they are not always published but are generally only available from the library shelf or through interlibrary loan; 2) the student who carried out the research may not be an experienced researcher and therefore you might have to treat their findings with more caution than published research. Note: Some dissertations are available from the DuBois Library databases. •    Web sites: Never a good source for a Lit Review. The fastest-growing source of information is on the Internet. It is impossible to characterize the information available but here are some hints about using electronic sources: 1) bear in mind that anyone can post information on the Internet so the quality may not be reliable, and 2) the information you find may be intended for a general audience and so may not be suitable for inclusion in your Lit Review (information for a general audience is usually less detailed and less scholarly). Note: This section does not refer to scholarly articles located on the DuBois Library databases. Databases are not web sites. •    Magazines: Not a good source for a Lit Review. Magazines intended for a general audience, e.g., Time, Us, National Enquirer, will not be useful in providing the sort of information you need. Specialized magazines may be more useful (for example business magazines for management students), but usually magazines are not useful for your research except as a starting point by providing news or general information about new discoveries, policies, etc. that you can further research in more specialized sources. How is a literature review different from an annotated bibliography? A Lit Review is written in the style of an expository essay; it has an introduction, body, and conclusion, and it is organized around a controlling idea or thesis. Compare this to an annotated Works Cited list, which is simply an alphabetized list of sources accompanied by summaries and evaluations (annotations). While a single source appears just once in an annotated Works Cited list, it may be referred to numerous times in a Lit Review, depending upon its importance in the field or relationship to other sources. Finally, a Lit Review includes its own in-text citations and Works Cited list.

How is a literature review different from a traditional research paper? A Lit Review may stand alone as a self-contained unit or be part of a research paper (such as a chapter in an honors thesis). Whereas the main body of a research paper focuses on the subject of your research, the Lit Review focuses on your sources. Put another way, in the research paper you use expert sources to support the discussion of your thesis; in a Lit Review, you discuss the sources themselves.

What are the characteristics of a literature review? Among the characteristics you should expect to see in any Lit Review are these: •    A Lit Review MUST have a Works Cited list that includes all references cited in the Lit Review. Do not list sources in the Works Cited list that are not directly cited in the Lit Review. •    A Lit Review is organized by subtopic, NOT by individual source. In a typical Lit Review, you may cite several references in the same paragraph and may cite the same reference in more than one paragraph if that source addresses more than one of the subtopics in the Lit Review. •    Typically, discussion of each source is quite brief. The contribution you make is organizing the ideas from the sources into a cogent argument or narrative that includes your perspectives. •    You should focus on citing the material that originates with each reference. This may require a careful reading of the reference. If the reference author refers to another source whose ideas are relevant or interesting, you are better off tracking down and using that reference. Citing a source that you haven’t read directly is called “grandfathering,” and it is not permitted. Never cite a source you haven’t read.

How is a literature review structured? The Lit Review is not just a descriptive list of the material available or a set of summaries. Demonstrate that you gained a thorough knowledge of the subject area being studied. A Lit Review should NOT be organized as a narrative of your own research process. A Lit Review that says essentially “First I found this source, then I found this one ….” is NOT acceptable. Therefore, like any expository essay, a Lit Review should have an introduction, body, and conclusion: The introduction should contain your research question (thesis statement), an explanation of its significance, and any other background information setting the context of your research. The body paragraphs contain your summative, comparative, and evaluative comments on the sources you’ve found. These comments may pertain to: •    historical background & early research findings •    recent developments •    areas of controversy among experts •    areas of agreement •    dominant views or leading authorities •    varying approaches to or perspectives on the subject •    qualitative comparisons and evaluations The conclusion summarizes major issues in the literature; it also establishes where your own research fits in and what directions you see for future research.

How is a literature review organized? While covering the range of matters listed above, a Lit Review—like any expository essay—should still have a single organizing principle expressed in a thesis statement. Examples of some common ones are these: •    Chronological — Use this organization if developments over time are important to explain the context of your research problem. Otherwise, using a chronological system is not the best way to organize your work. •    Thematic — Depending on your topic, you could organize your Lit Review by time, geographic location, gender, nationality, or another appropriate theme. •    Methodological — What approaches have researchers taken in studying the issue you’re researching? Is your topic suited best for library research or field research? •    Qualitative — Is there a great deal of difference in the quality of research conducted on your topic?

What are some strategies for writing a good literature review? The process of writing a Lit Review typically involves a number of steps. These should include the following: •    Deciding on a relatively focused topic or question. •    Searching for relevant and relatively current literature (books, journal articles, etc. – the mix of these depends on your topic or thesis statement). It is important to locate and comment on the most important works in your chosen field. Failure to include such works might be considered a major failing of your review. The more you research and read, the more you become aware of names that are mentioned repeatedly as influential and even seminal authorities. •    Reading the materials you have found and noting how they approach your topic or question: It isn’t necessary to read every word of a book to learn what an author says about a particular subject. Peruse the index. Skim through the book or article. A quick read through the introduction or the conclusion gives a gist of the book’s or article’s thesis, general points, or argument. Begin with the most recent studies and work backwards. A recent article’s list of references or bibliography might provide you with valuable works to consult. •    Preparing a working outline for your Lit Review and grouping notes from your references in the appropriate section of your outline: Use note cards with citations and annotations, photocopied articles with points highlighted and notes in the margins, or whatever methods helps you keep your information organized. •    Take good notes: Don’t trust your memory. Record all research. Write out the complete bibliographic citation for each work. Record the page number too, because you’ll need it for your in-text citations. (Unless you are citing an entire book or journal article, the in-text citation must include a page number or it’s considered incomplete/inaccurate.) Write direct quotations word for word. Use quotation marks, so it can be recognized as a direct quote. Avoid using too many direct quotations. Take down the substance of the author’s ideas in your own words (paraphrase). IMPORTANT: Most of the review should be primarily in your own words with appropriate documentation of other’s ideas. Don’t take too many notes from a single source or two. Use a wide range of sources. •    Evaluating the information: After reading a lot of material, researchers must carefully evaluate it and decide what should be included in the literature review. Obviously researchers must be objective. Keep an open mind and look at a topic from different vantage points. Determine the objectivity of the material. Who funded the research studies? Who actually performed the research? For a contentious topic, present as equally as possible opposing positions. Be objective. Don’t overemphasize one side. •    Writing and revising the narrative: Keep your audience in mind as your write. Keep your paragraphs short and use subheadings to clarify the structure. Subheadings break the material into readable units. A Lit Review must be organized around and directly related to the thesis or research question you are developing. It must identify areas of controversy in the literature and formulate questions that need further research.

Some traps to avoid: •    Trying to read everything! As you might already have discovered, if you try to be comprehensive you will never be able to finish the reading! The Lit Review does not have to be exhaustive; the objective is not to list as many books, articles, and reports as possible. The idea of the Lit Review is not to provide a summary of all the published work that relates to your research, but a survey of the most relevant and significant work. The Lit Review should contain the most pertinent related studies and show an awareness of important past research and practices and promising current research and practices in the field. •    Reading but not writing! It’s easier to read than to write: given the choice, most of us would rather sit down with a cup of coffee and read yet another article instead of putting ourselves in front of the computer to write about what we have already read! Writing takes much more effort, doesn’t it? However, writing can help you to understand and find relationships between the works you’ve read, so don’t put writing off until you’ve “finished” reading – after all, you will probably still be doing some reading all the way through to the end of your research project. Also, don’t think of what you first write as being the final or near-final version. Writing is a way of thinking, so allow yourself to write as many drafts as you need, changing your ideas and information as you learn more about the context of your research problem. •    Not keeping bibliographic information! The moment will come when you have to write your Works Cited list . . . and then you realize you have forgotten to keep the information you need, and that you never got around to putting references into your work. The only solution is to spend a lot of time in the library tracking down all those sources that you read and going through your writing to find which information came from which source. To avoid this nightmare, always keep this information in your notes. Always put references into your writing.

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A literature review surveys prior research published in books, scholarly articles, and any other sources relevant to a particular issue, area of research, or theory, and by so doing, provides a description, summary, and critical evaluation of these works in relation to the research problem being investigated. Literature reviews are designed to provide an overview of sources you have used in researching a particular topic and to demonstrate to your readers how your research fits within existing scholarship about the topic.

Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper . Fourth edition. Thousand Oaks, CA: SAGE, 2014.

Importance of a Good Literature Review

A literature review may consist of simply a summary of key sources, but in the social sciences, a literature review usually has an organizational pattern and combines both summary and synthesis, often within specific conceptual categories . A summary is a recap of the important information of the source, but a synthesis is a re-organization, or a reshuffling, of that information in a way that informs how you are planning to investigate a research problem. The analytical features of a literature review might:

• Give a new interpretation of old material or combine new with old interpretations,
• Trace the intellectual progression of the field, including major debates,
• Depending on the situation, evaluate the sources and advise the reader on the most pertinent or relevant research, or
• Usually in the conclusion of a literature review, identify where gaps exist in how a problem has been researched to date.

Given this, the purpose of a literature review is to:

• Place each work in the context of its contribution to understanding the research problem being studied.
• Describe the relationship of each work to the others under consideration.
• Identify new ways to interpret prior research.
• Reveal any gaps that exist in the literature.
• Resolve conflicts amongst seemingly contradictory previous studies.
• Identify areas of prior scholarship to prevent duplication of effort.
• Point the way in fulfilling a need for additional research.
• Locate your own research within the context of existing literature [very important].

Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper. 2nd ed. Thousand Oaks, CA: Sage, 2005; Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1998; Jesson, Jill. Doing Your Literature Review: Traditional and Systematic Techniques . Los Angeles, CA: SAGE, 2011; Knopf, Jeffrey W. "Doing a Literature Review." PS: Political Science and Politics 39 (January 2006): 127-132; Ridley, Diana. The Literature Review: A Step-by-Step Guide for Students . 2nd ed. Los Angeles, CA: SAGE, 2012.

Types of Literature Reviews

It is important to think of knowledge in a given field as consisting of three layers. First, there are the primary studies that researchers conduct and publish. Second are the reviews of those studies that summarize and offer new interpretations built from and often extending beyond the primary studies. Third, there are the perceptions, conclusions, opinion, and interpretations that are shared informally among scholars that become part of the body of epistemological traditions within the field.

In composing a literature review, it is important to note that it is often this third layer of knowledge that is cited as "true" even though it often has only a loose relationship to the primary studies and secondary literature reviews. Given this, while literature reviews are designed to provide an overview and synthesis of pertinent sources you have explored, there are a number of approaches you could adopt depending upon the type of analysis underpinning your study.

Argumentative Review This form examines literature selectively in order to support or refute an argument, deeply embedded assumption, or philosophical problem already established in the literature. The purpose is to develop a body of literature that establishes a contrarian viewpoint. Given the value-laden nature of some social science research [e.g., educational reform; immigration control], argumentative approaches to analyzing the literature can be a legitimate and important form of discourse. However, note that they can also introduce problems of bias when they are used to make summary claims of the sort found in systematic reviews [see below].

Integrative Review Considered a form of research that reviews, critiques, and synthesizes representative literature on a topic in an integrated way such that new frameworks and perspectives on the topic are generated. The body of literature includes all studies that address related or identical hypotheses or research problems. A well-done integrative review meets the same standards as primary research in regard to clarity, rigor, and replication. This is the most common form of review in the social sciences.

Historical Review Few things rest in isolation from historical precedent. Historical literature reviews focus on examining research throughout a period of time, often starting with the first time an issue, concept, theory, phenomena emerged in the literature, then tracing its evolution within the scholarship of a discipline. The purpose is to place research in a historical context to show familiarity with state-of-the-art developments and to identify the likely directions for future research.

Methodological Review A review does not always focus on what someone said [findings], but how they came about saying what they say [method of analysis]. Reviewing methods of analysis provides a framework of understanding at different levels [i.e. those of theory, substantive fields, research approaches, and data collection and analysis techniques], how researchers draw upon a wide variety of knowledge ranging from the conceptual level to practical documents for use in fieldwork in the areas of ontological and epistemological consideration, quantitative and qualitative integration, sampling, interviewing, data collection, and data analysis. This approach helps highlight ethical issues which you should be aware of and consider as you go through your own study.

Systematic Review This form consists of an overview of existing evidence pertinent to a clearly formulated research question, which uses pre-specified and standardized methods to identify and critically appraise relevant research, and to collect, report, and analyze data from the studies that are included in the review. The goal is to deliberately document, critically evaluate, and summarize scientifically all of the research about a clearly defined research problem . Typically it focuses on a very specific empirical question, often posed in a cause-and-effect form, such as "To what extent does A contribute to B?" This type of literature review is primarily applied to examining prior research studies in clinical medicine and allied health fields, but it is increasingly being used in the social sciences.

Theoretical Review The purpose of this form is to examine the corpus of theory that has accumulated in regard to an issue, concept, theory, phenomena. The theoretical literature review helps to establish what theories already exist, the relationships between them, to what degree the existing theories have been investigated, and to develop new hypotheses to be tested. Often this form is used to help establish a lack of appropriate theories or reveal that current theories are inadequate for explaining new or emerging research problems. The unit of analysis can focus on a theoretical concept or a whole theory or framework.

NOTE : Most often the literature review will incorporate some combination of types. For example, a review that examines literature supporting or refuting an argument, assumption, or philosophical problem related to the research problem will also need to include writing supported by sources that establish the history of these arguments in the literature.

Baumeister, Roy F. and Mark R. Leary. "Writing Narrative Literature Reviews."  Review of General Psychology 1 (September 1997): 311-320; Mark R. Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper . 2nd ed. Thousand Oaks, CA: Sage, 2005; Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1998; Kennedy, Mary M. "Defining a Literature." Educational Researcher 36 (April 2007): 139-147; Petticrew, Mark and Helen Roberts. Systematic Reviews in the Social Sciences: A Practical Guide . Malden, MA: Blackwell Publishers, 2006; Torracro, Richard. "Writing Integrative Literature Reviews: Guidelines and Examples." Human Resource Development Review 4 (September 2005): 356-367; Rocco, Tonette S. and Maria S. Plakhotnik. "Literature Reviews, Conceptual Frameworks, and Theoretical Frameworks: Terms, Functions, and Distinctions." Human Ressource Development Review 8 (March 2008): 120-130; Sutton, Anthea. Systematic Approaches to a Successful Literature Review . Los Angeles, CA: Sage Publications, 2016.

Structure and Writing Style

I.  Thinking About Your Literature Review

The structure of a literature review should include the following in support of understanding the research problem :

• An overview of the subject, issue, or theory under consideration, along with the objectives of the literature review,
• Division of works under review into themes or categories [e.g. works that support a particular position, those against, and those offering alternative approaches entirely],
• An explanation of how each work is similar to and how it varies from the others,
• Conclusions as to which pieces are best considered in their argument, are most convincing of their opinions, and make the greatest contribution to the understanding and development of their area of research.

The critical evaluation of each work should consider :

• Provenance -- what are the author's credentials? Are the author's arguments supported by evidence [e.g. primary historical material, case studies, narratives, statistics, recent scientific findings]?
• Methodology -- were the techniques used to identify, gather, and analyze the data appropriate to addressing the research problem? Was the sample size appropriate? Were the results effectively interpreted and reported?
• Objectivity -- is the author's perspective even-handed or prejudicial? Is contrary data considered or is certain pertinent information ignored to prove the author's point?
• Persuasiveness -- which of the author's theses are most convincing or least convincing?
• Validity -- are the author's arguments and conclusions convincing? Does the work ultimately contribute in any significant way to an understanding of the subject?

II.  Development of the Literature Review

Four Basic Stages of Writing 1.  Problem formulation -- which topic or field is being examined and what are its component issues? 2.  Literature search -- finding materials relevant to the subject being explored. 3.  Data evaluation -- determining which literature makes a significant contribution to the understanding of the topic. 4.  Analysis and interpretation -- discussing the findings and conclusions of pertinent literature.

Consider the following issues before writing the literature review: Clarify If your assignment is not specific about what form your literature review should take, seek clarification from your professor by asking these questions: 1.  Roughly how many sources would be appropriate to include? 2.  What types of sources should I review (books, journal articles, websites; scholarly versus popular sources)? 3.  Should I summarize, synthesize, or critique sources by discussing a common theme or issue? 4.  Should I evaluate the sources in any way beyond evaluating how they relate to understanding the research problem? 5.  Should I provide subheadings and other background information, such as definitions and/or a history? Find Models Use the exercise of reviewing the literature to examine how authors in your discipline or area of interest have composed their literature review sections. Read them to get a sense of the types of themes you might want to look for in your own research or to identify ways to organize your final review. The bibliography or reference section of sources you've already read, such as required readings in the course syllabus, are also excellent entry points into your own research. Narrow the Topic The narrower your topic, the easier it will be to limit the number of sources you need to read in order to obtain a good survey of relevant resources. Your professor will probably not expect you to read everything that's available about the topic, but you'll make the act of reviewing easier if you first limit scope of the research problem. A good strategy is to begin by searching the USC Libraries Catalog for recent books about the topic and review the table of contents for chapters that focuses on specific issues. You can also review the indexes of books to find references to specific issues that can serve as the focus of your research. For example, a book surveying the history of the Israeli-Palestinian conflict may include a chapter on the role Egypt has played in mediating the conflict, or look in the index for the pages where Egypt is mentioned in the text. Consider Whether Your Sources are Current Some disciplines require that you use information that is as current as possible. This is particularly true in disciplines in medicine and the sciences where research conducted becomes obsolete very quickly as new discoveries are made. However, when writing a review in the social sciences, a survey of the history of the literature may be required. In other words, a complete understanding the research problem requires you to deliberately examine how knowledge and perspectives have changed over time. Sort through other current bibliographies or literature reviews in the field to get a sense of what your discipline expects. You can also use this method to explore what is considered by scholars to be a "hot topic" and what is not.

III.  Ways to Organize Your Literature Review

Chronology of Events If your review follows the chronological method, you could write about the materials according to when they were published. This approach should only be followed if a clear path of research building on previous research can be identified and that these trends follow a clear chronological order of development. For example, a literature review that focuses on continuing research about the emergence of German economic power after the fall of the Soviet Union. By Publication Order your sources by publication chronology, then, only if the order demonstrates a more important trend. For instance, you could order a review of literature on environmental studies of brown fields if the progression revealed, for example, a change in the soil collection practices of the researchers who wrote and/or conducted the studies. Thematic [“conceptual categories”] A thematic literature review is the most common approach to summarizing prior research in the social and behavioral sciences. Thematic reviews are organized around a topic or issue, rather than the progression of time, although the progression of time may still be incorporated into a thematic review. For example, a review of the Internet’s impact on American presidential politics could focus on the development of online political satire. While the study focuses on one topic, the Internet’s impact on American presidential politics, it would still be organized chronologically reflecting technological developments in media. The difference in this example between a "chronological" and a "thematic" approach is what is emphasized the most: themes related to the role of the Internet in presidential politics. Note that more authentic thematic reviews tend to break away from chronological order. A review organized in this manner would shift between time periods within each section according to the point being made. Methodological A methodological approach focuses on the methods utilized by the researcher. For the Internet in American presidential politics project, one methodological approach would be to look at cultural differences between the portrayal of American presidents on American, British, and French websites. Or the review might focus on the fundraising impact of the Internet on a particular political party. A methodological scope will influence either the types of documents in the review or the way in which these documents are discussed.

Other Sections of Your Literature Review Once you've decided on the organizational method for your literature review, the sections you need to include in the paper should be easy to figure out because they arise from your organizational strategy. In other words, a chronological review would have subsections for each vital time period; a thematic review would have subtopics based upon factors that relate to the theme or issue. However, sometimes you may need to add additional sections that are necessary for your study, but do not fit in the organizational strategy of the body. What other sections you include in the body is up to you. However, only include what is necessary for the reader to locate your study within the larger scholarship about the research problem.

Here are examples of other sections, usually in the form of a single paragraph, you may need to include depending on the type of review you write:

• Current Situation : Information necessary to understand the current topic or focus of the literature review.
• Sources Used : Describes the methods and resources [e.g., databases] you used to identify the literature you reviewed.
• History : The chronological progression of the field, the research literature, or an idea that is necessary to understand the literature review, if the body of the literature review is not already a chronology.
• Selection Methods : Criteria you used to select (and perhaps exclude) sources in your literature review. For instance, you might explain that your review includes only peer-reviewed [i.e., scholarly] sources.
• Standards : Description of the way in which you present your information.
• Questions for Further Research : What questions about the field has the review sparked? How will you further your research as a result of the review?

IV.  Writing Your Literature Review

Once you've settled on how to organize your literature review, you're ready to write each section. When writing your review, keep in mind these issues.

Use Evidence A literature review section is, in this sense, just like any other academic research paper. Your interpretation of the available sources must be backed up with evidence [citations] that demonstrates that what you are saying is valid. Be Selective Select only the most important points in each source to highlight in the review. The type of information you choose to mention should relate directly to the research problem, whether it is thematic, methodological, or chronological. Related items that provide additional information, but that are not key to understanding the research problem, can be included in a list of further readings . Use Quotes Sparingly Some short quotes are appropriate if you want to emphasize a point, or if what an author stated cannot be easily paraphrased. Sometimes you may need to quote certain terminology that was coined by the author, is not common knowledge, or taken directly from the study. Do not use extensive quotes as a substitute for using your own words in reviewing the literature. Summarize and Synthesize Remember to summarize and synthesize your sources within each thematic paragraph as well as throughout the review. Recapitulate important features of a research study, but then synthesize it by rephrasing the study's significance and relating it to your own work and the work of others. Keep Your Own Voice While the literature review presents others' ideas, your voice [the writer's] should remain front and center. For example, weave references to other sources into what you are writing but maintain your own voice by starting and ending the paragraph with your own ideas and wording. Use Caution When Paraphrasing When paraphrasing a source that is not your own, be sure to represent the author's information or opinions accurately and in your own words. Even when paraphrasing an author’s work, you still must provide a citation to that work.

V.  Common Mistakes to Avoid

These are the most common mistakes made in reviewing social science research literature.

• Sources in your literature review do not clearly relate to the research problem;
• You do not take sufficient time to define and identify the most relevant sources to use in the literature review related to the research problem;
• Relies exclusively on secondary analytical sources rather than including relevant primary research studies or data;
• Uncritically accepts another researcher's findings and interpretations as valid, rather than examining critically all aspects of the research design and analysis;
• Does not describe the search procedures that were used in identifying the literature to review;
• Reports isolated statistical results rather than synthesizing them in chi-squared or meta-analytic methods; and,
• Only includes research that validates assumptions and does not consider contrary findings and alternative interpretations found in the literature.

Cook, Kathleen E. and Elise Murowchick. “Do Literature Review Skills Transfer from One Course to Another?” Psychology Learning and Teaching 13 (March 2014): 3-11; Fink, Arlene. Conducting Research Literature Reviews: From the Internet to Paper . 2nd ed. Thousand Oaks, CA: Sage, 2005; Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1998; Jesson, Jill. Doing Your Literature Review: Traditional and Systematic Techniques . London: SAGE, 2011; Literature Review Handout. Online Writing Center. Liberty University; Literature Reviews. The Writing Center. University of North Carolina; Onwuegbuzie, Anthony J. and Rebecca Frels. Seven Steps to a Comprehensive Literature Review: A Multimodal and Cultural Approach . Los Angeles, CA: SAGE, 2016; Ridley, Diana. The Literature Review: A Step-by-Step Guide for Students . 2nd ed. Los Angeles, CA: SAGE, 2012; Randolph, Justus J. “A Guide to Writing the Dissertation Literature Review." Practical Assessment, Research, and Evaluation. vol. 14, June 2009; Sutton, Anthea. Systematic Approaches to a Successful Literature Review . Los Angeles, CA: Sage Publications, 2016; Taylor, Dena. The Literature Review: A Few Tips On Conducting It. University College Writing Centre. University of Toronto; Writing a Literature Review. Academic Skills Centre. University of Canberra.

Writing Tip

Break Out of Your Disciplinary Box!

Thinking interdisciplinarily about a research problem can be a rewarding exercise in applying new ideas, theories, or concepts to an old problem. For example, what might cultural anthropologists say about the continuing conflict in the Middle East? In what ways might geographers view the need for better distribution of social service agencies in large cities than how social workers might study the issue? You don’t want to substitute a thorough review of core research literature in your discipline for studies conducted in other fields of study. However, particularly in the social sciences, thinking about research problems from multiple vectors is a key strategy for finding new solutions to a problem or gaining a new perspective. Consult with a librarian about identifying research databases in other disciplines; almost every field of study has at least one comprehensive database devoted to indexing its research literature.

Frodeman, Robert. The Oxford Handbook of Interdisciplinarity . New York: Oxford University Press, 2010.

Another Writing Tip

Don't Just Review for Content!

While conducting a review of the literature, maximize the time you devote to writing this part of your paper by thinking broadly about what you should be looking for and evaluating. Review not just what scholars are saying, but how are they saying it. Some questions to ask:

• How are they organizing their ideas?
• What methods have they used to study the problem?
• What theories have been used to explain, predict, or understand their research problem?
• What sources have they cited to support their conclusions?
• How have they used non-textual elements [e.g., charts, graphs, figures, etc.] to illustrate key points?

When you begin to write your literature review section, you'll be glad you dug deeper into how the research was designed and constructed because it establishes a means for developing more substantial analysis and interpretation of the research problem.

Hart, Chris. Doing a Literature Review: Releasing the Social Science Research Imagination . Thousand Oaks, CA: Sage Publications, 1 998.

Yet Another Writing Tip

When Do I Know I Can Stop Looking and Move On?

Here are several strategies you can utilize to assess whether you've thoroughly reviewed the literature:

• Look for repeating patterns in the research findings . If the same thing is being said, just by different people, then this likely demonstrates that the research problem has hit a conceptual dead end. At this point consider: Does your study extend current research?  Does it forge a new path? Or, does is merely add more of the same thing being said?
• Look at sources the authors cite to in their work . If you begin to see the same researchers cited again and again, then this is often an indication that no new ideas have been generated to address the research problem.
• Search Google Scholar to identify who has subsequently cited leading scholars already identified in your literature review [see next sub-tab]. This is called citation tracking and there are a number of sources that can help you identify who has cited whom, particularly scholars from outside of your discipline. Here again, if the same authors are being cited again and again, this may indicate no new literature has been written on the topic.

Onwuegbuzie, Anthony J. and Rebecca Frels. Seven Steps to a Comprehensive Literature Review: A Multimodal and Cultural Approach . Los Angeles, CA: Sage, 2016; Sutton, Anthea. Systematic Approaches to a Successful Literature Review . Los Angeles, CA: Sage Publications, 2016.

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How To Write An A-Grade Literature Review

3 straightforward steps (with examples) + free template.

By: Derek Jansen (MBA) | Expert Reviewed By: Dr. Eunice Rautenbach | October 2019

Quality research is about building onto the existing work of others , “standing on the shoulders of giants”, as Newton put it. The literature review chapter of your dissertation, thesis or research project is where you synthesise this prior work and lay the theoretical foundation for your own research.

Long story short, this chapter is a pretty big deal, which is why you want to make sure you get it right . In this post, I’ll show you exactly how to write a literature review in three straightforward steps, so you can conquer this vital chapter (the smart way).

Overview: The Literature Review Process

• Understanding the “ why “
• Finding the relevant literature
• Cataloguing and synthesising the information
• Outlining & writing up your literature review
• Example of a literature review

But first, the “why”…

Before we unpack how to write the literature review chapter, we’ve got to look at the why . To put it bluntly, if you don’t understand the function and purpose of the literature review process, there’s no way you can pull it off well. So, what exactly is the purpose of the literature review?

Well, there are (at least) four core functions:

• For you to gain an understanding (and demonstrate this understanding) of where the research is at currently, what the key arguments and disagreements are.
• For you to identify the gap(s) in the literature and then use this as justification for your own research topic.
• To help you build a conceptual framework for empirical testing (if applicable to your research topic).
• To inform your methodological choices and help you source tried and tested questionnaires (for interviews ) and measurement instruments (for surveys ).

Most students understand the first point but don’t give any thought to the rest. To get the most from the literature review process, you must keep all four points front of mind as you review the literature (more on this shortly), or you’ll land up with a wonky foundation.

Okay – with the why out the way, let’s move on to the how . As mentioned above, writing your literature review is a process, which I’ll break down into three steps:

• Finding the most suitable literature
• Understanding , distilling and organising the literature
• Planning and writing up your literature review chapter

Importantly, you must complete steps one and two before you start writing up your chapter. I know it’s very tempting, but don’t try to kill two birds with one stone and write as you read. You’ll invariably end up wasting huge amounts of time re-writing and re-shaping, or you’ll just land up with a disjointed, hard-to-digest mess . Instead, you need to read first and distil the information, then plan and execute the writing.

Step 1: Find the relevant literature

Naturally, the first step in the literature review journey is to hunt down the existing research that’s relevant to your topic. While you probably already have a decent base of this from your research proposal , you need to expand on this substantially in the dissertation or thesis itself.

Essentially, you need to be looking for any existing literature that potentially helps you answer your research question (or develop it, if that’s not yet pinned down). There are numerous ways to find relevant literature, but I’ll cover my top four tactics here. I’d suggest combining all four methods to ensure that nothing slips past you:

Method 1 – Google Scholar Scrubbing

Google’s academic search engine, Google Scholar , is a great starting point as it provides a good high-level view of the relevant journal articles for whatever keyword you throw at it. Most valuably, it tells you how many times each article has been cited, which gives you an idea of how credible (or at least, popular) it is. Some articles will be free to access, while others will require an account, which brings us to the next method.

Method 2 – University Database Scrounging

Generally, universities provide students with access to an online library, which provides access to many (but not all) of the major journals.

So, if you find an article using Google Scholar that requires paid access (which is quite likely), search for that article in your university’s database – if it’s listed there, you’ll have access. Note that, generally, the search engine capabilities of these databases are poor, so make sure you search for the exact article name, or you might not find it.

Method 3 – Journal Article Snowballing

At the end of every academic journal article, you’ll find a list of references. As with any academic writing, these references are the building blocks of the article, so if the article is relevant to your topic, there’s a good chance a portion of the referenced works will be too. Do a quick scan of the titles and see what seems relevant, then search for the relevant ones in your university’s database.

Method 4 – Dissertation Scavenging

Similar to Method 3 above, you can leverage other students’ dissertations. All you have to do is skim through literature review chapters of existing dissertations related to your topic and you’ll find a gold mine of potential literature. Usually, your university will provide you with access to previous students’ dissertations, but you can also find a much larger selection in the following databases:

• Open Access Theses & Dissertations
• Stanford SearchWorks

Keep in mind that dissertations and theses are not as academically sound as published, peer-reviewed journal articles (because they’re written by students, not professionals), so be sure to check the credibility of any sources you find using this method. You can do this by assessing the citation count of any given article in Google Scholar. If you need help with assessing the credibility of any article, or with finding relevant research in general, you can chat with one of our Research Specialists .

Alright – with a good base of literature firmly under your belt, it’s time to move onto the next step.

Need a helping hand?

Step 2: Log, catalogue and synthesise

Once you’ve built a little treasure trove of articles, it’s time to get reading and start digesting the information – what does it all mean?

While I present steps one and two (hunting and digesting) as sequential, in reality, it’s more of a back-and-forth tango – you’ll read a little , then have an idea, spot a new citation, or a new potential variable, and then go back to searching for articles. This is perfectly natural – through the reading process, your thoughts will develop , new avenues might crop up, and directional adjustments might arise. This is, after all, one of the main purposes of the literature review process (i.e. to familiarise yourself with the current state of research in your field).

As you’re working through your treasure chest, it’s essential that you simultaneously start organising the information. There are three aspects to this:

• Logging reference information
• Building an organised catalogue
• Distilling and synthesising the information

I’ll discuss each of these below:

2.1 – Log the reference information

As you read each article, you should add it to your reference management software. I usually recommend Mendeley for this purpose (see the Mendeley 101 video below), but you can use whichever software you’re comfortable with. Most importantly, make sure you load EVERY article you read into your reference manager, even if it doesn’t seem very relevant at the time.

2.2 – Build an organised catalogue

In the beginning, you might feel confident that you can remember who said what, where, and what their main arguments were. Trust me, you won’t. If you do a thorough review of the relevant literature (as you must!), you’re going to read many, many articles, and it’s simply impossible to remember who said what, when, and in what context . Also, without the bird’s eye view that a catalogue provides, you’ll miss connections between various articles, and have no view of how the research developed over time. Simply put, it’s essential to build your own catalogue of the literature.

I would suggest using Excel to build your catalogue, as it allows you to run filters, colour code and sort – all very useful when your list grows large (which it will). How you lay your spreadsheet out is up to you, but I’d suggest you have the following columns (at minimum):

• Author, date, title – Start with three columns containing this core information. This will make it easy for you to search for titles with certain words, order research by date, or group by author.
• Categories or keywords – You can either create multiple columns, one for each category/theme and then tick the relevant categories, or you can have one column with keywords.
• Key arguments/points – Use this column to succinctly convey the essence of the article, the key arguments and implications thereof for your research.
• Context – Note the socioeconomic context in which the research was undertaken. For example, US-based, respondents aged 25-35, lower- income, etc. This will be useful for making an argument about gaps in the research.
• Methodology – Note which methodology was used and why. Also, note any issues you feel arise due to the methodology. Again, you can use this to make an argument about gaps in the research.
• Quotations – Note down any quoteworthy lines you feel might be useful later.
• Notes – Make notes about anything not already covered. For example, linkages to or disagreements with other theories, questions raised but unanswered, shortcomings or limitations, and so forth.

If you’d like, you can try out our free catalog template here (see screenshot below).

2.3 – Digest and synthesise

Most importantly, as you work through the literature and build your catalogue, you need to synthesise all the information in your own mind – how does it all fit together? Look for links between the various articles and try to develop a bigger picture view of the state of the research. Some important questions to ask yourself are:

• What answers does the existing research provide to my own research questions ?
• Which points do the researchers agree (and disagree) on?
• How has the research developed over time?
• Where do the gaps in the current research lie?

To help you develop a big-picture view and synthesise all the information, you might find mind mapping software such as Freemind useful. Alternatively, if you’re a fan of physical note-taking, investing in a large whiteboard might work for you.

Step 3: Outline and write it up!

Once you’re satisfied that you have digested and distilled all the relevant literature in your mind, it’s time to put pen to paper (or rather, fingers to keyboard). There are two steps here – outlining and writing:

3.1 – Draw up your outline

Having spent so much time reading, it might be tempting to just start writing up without a clear structure in mind. However, it’s critically important to decide on your structure and develop a detailed outline before you write anything. Your literature review chapter needs to present a clear, logical and an easy to follow narrative – and that requires some planning. Don’t try to wing it!

Naturally, you won’t always follow the plan to the letter, but without a detailed outline, you’re more than likely going to end up with a disjointed pile of waffle , and then you’re going to spend a far greater amount of time re-writing, hacking and patching. The adage, “measure twice, cut once” is very suitable here.

In terms of structure, the first decision you’ll have to make is whether you’ll lay out your review thematically (into themes) or chronologically (by date/period). The right choice depends on your topic, research objectives and research questions, which we discuss in this article .

Once that’s decided, you need to draw up an outline of your entire chapter in bullet point format. Try to get as detailed as possible, so that you know exactly what you’ll cover where, how each section will connect to the next, and how your entire argument will develop throughout the chapter. Also, at this stage, it’s a good idea to allocate rough word count limits for each section, so that you can identify word count problems before you’ve spent weeks or months writing!

PS – check out our free literature review chapter template…

3.2 – Get writing

With a detailed outline at your side, it’s time to start writing up (finally!). At this stage, it’s common to feel a bit of writer’s block and find yourself procrastinating under the pressure of finally having to put something on paper. To help with this, remember that the objective of the first draft is not perfection – it’s simply to get your thoughts out of your head and onto paper, after which you can refine them. The structure might change a little, the word count allocations might shift and shuffle, and you might add or remove a section – that’s all okay. Don’t worry about all this on your first draft – just get your thoughts down on paper.

Once you’ve got a full first draft (however rough it may be), step away from it for a day or two (longer if you can) and then come back at it with fresh eyes. Pay particular attention to the flow and narrative – does it fall fit together and flow from one section to another smoothly? Now’s the time to try to improve the linkage from each section to the next, tighten up the writing to be more concise, trim down word count and sand it down into a more digestible read.

Once you’ve done that, give your writing to a friend or colleague who is not a subject matter expert and ask them if they understand the overall discussion. The best way to assess this is to ask them to explain the chapter back to you. This technique will give you a strong indication of which points were clearly communicated and which weren’t. If you’re working with Grad Coach, this is a good time to have your Research Specialist review your chapter.

Finally, tighten it up and send it off to your supervisor for comment. Some might argue that you should be sending your work to your supervisor sooner than this (indeed your university might formally require this), but in my experience, supervisors are extremely short on time (and often patience), so, the more refined your chapter is, the less time they’ll waste on addressing basic issues (which you know about already) and the more time they’ll spend on valuable feedback that will increase your mark-earning potential.

Literature Review Example

In the video below, we unpack an actual literature review so that you can see how all the core components come together in reality.

Let’s Recap

In this post, we’ve covered how to research and write up a high-quality literature review chapter. Let’s do a quick recap of the key takeaways:

• It is essential to understand the WHY of the literature review before you read or write anything. Make sure you understand the 4 core functions of the process.
• The first step is to hunt down the relevant literature . You can do this using Google Scholar, your university database, the snowballing technique and by reviewing other dissertations and theses.
• Next, you need to log all the articles in your reference manager , build your own catalogue of literature and synthesise all the research.
• Following that, you need to develop a detailed outline of your entire chapter – the more detail the better. Don’t start writing without a clear outline (on paper, not in your head!)
• Write up your first draft in rough form – don’t aim for perfection. Remember, done beats perfect.
• Refine your second draft and get a layman’s perspective on it . Then tighten it up and submit it to your supervisor.

Psst… there’s more!

This post is an extract from our bestselling short course, Literature Review Bootcamp . If you want to work smart, you don't want to miss this .

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38 Comments

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You’re welcome, Yinka. Thank you for the kind words. All the best writing your literature review.

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Thank you so much Derek for such useful information on writing up a good literature review. I am at a stage where I need to start writing my one. My proposal was accepted late last year but I honestly did not know where to start

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University Libraries

Literature review.

• What is a Literature Review?
• What is Its Purpose?
• 1. Select a Topic
• 2. Set the Topic in Context
• 3. Types of Information Sources
• 4. Use Information Sources
• 5. Get the Information
• 6. Organize / Manage the Information
• 7. Position the Literature Review
• 8. Write the Literature Review

A literature review is a comprehensive summary of previous research on a topic. The literature review surveys scholarly articles, books, and other sources relevant to a particular area of research.  The review should enumerate, describe, summarize, objectively evaluate and clarify this previous research.  It should give a theoretical base for the research and help you (the author) determine the nature of your research.  The literature review acknowledges the work of previous researchers, and in so doing, assures the reader that your work has been well conceived.  It is assumed that by mentioning a previous work in the field of study, that the author has read, evaluated, and assimiliated that work into the work at hand.

A literature review creates a "landscape" for the reader, giving her or him a full understanding of the developments in the field.  This landscape informs the reader that the author has indeed assimilated all (or the vast majority of) previous, significant works in the field into her or his research. 

 "In writing the literature review, the purpose is to convey to the reader what knowledge and ideas have been established on a topic, and what their strengths and weaknesses are. The literature review must be defined by a guiding concept (eg. your research objective, the problem or issue you are discussing, or your argumentative thesis). It is not just a descriptive list of the material available, or a set of summaries.( http://www.writing.utoronto.ca/advice/specific-types-of-writing/literature-review )

Recommended Reading

• Next: What is Its Purpose? >>
• Last Updated: Oct 2, 2023 12:34 PM

3 Literature Review

Charitianne Williams

By the end of this chapter, you will be able to do the following:

• Understand the purpose and function of a literature review.
• Structure a literature review according to basic genre expectations.
• Synthesize ideas from multiple sources using a synthesis matrix.
• Choose between narrative or parenthetical citation and direct quoting, or paraphrase with intent and purpose.

I. Introduction

The purpose of a literature review is just that—it reviews. This means that literature reviews examine a text after it was produced, with all the benefits that hindsight allows a reader. In popular culture, we commonly review movies, restaurants, vacation spots, products, etc. In those reviews, you look back at the single thing you are reviewing and your experience with it. You focus on the strengths and weaknesses of your experience and judge the experience as positive or negative while recommending or not recommending the place or product and explaining why.

An academic literature review does something different, although some of the skills and strategies you use remain the same. The job of a literature review is to examine a collection of research or scholarship (not a single thing or text) on a given topic and show how that scholarship fits together. Literature reviews summarize, describe, evaluate, and synthesize the work of other authors and researchers while looking for common trends/patterns, themes, inconsistencies, and gaps in this previous research. The main strategy writers of a literature review use is synthesis.

SYNTHESIS: the combination of ideas and elements to form a complete system or theory.

A good metaphor for synthesis is cooking! Imagine the ingredients for a loaf of bread laid out on a kitchen cabinet. Each ingredient—eggs, milk, flour, sugar, salt, yeast—have their own purpose and can be combined in different ways to form food other than bread. Knowing all of those individual attributes that make an egg an egg, or the difference between yeast and flour, is what makes you a chef. When you combine all these ingredients according to the recipe, you get something different than all the ingredients on their own: and most of us would rather eat a slice of bread than a spoonful of flour. The product of synthesis is like bread. Synthesis takes a list of ingredients and makes them into something more than the ingredients alone.

Usually, the writers of a literature review will start with a question that they want to answer through informed and research-based evidence gathered while reading others’ work on related topics. The “thesis” or controlling idea of a literature review may be that same question ( “This review seeks to answer…” ) or it may be a statement describing the reviewed research. The thesis reflects the purpose of the literature review as a genre and is different from the thesis you will write for the research paper that argues a claim or asserts a new idea.

Example 3.1: Look at this thesis statement taken from the introduction of a literature review in environmental psychology on the relationship between “nature sounds” and restorative environments:

From this example, we can learn many things about literature reviews:

• They are explicit and focused on their topic. The opening states an observable truth about the current research ( emphasizes nature ), is followed by a general condition ( positive psychological experiences) within that research, and then finally focuses on describing how a particular outcome is achieved (listening to nature sounds is restorative).
• They seek to pre vent or eliminate misunderstanding. Note the use of specialized key terms, exacting transitional phrases, and meaningful verbs in the thesis such as “ restorative environments,” “in particular,” and “ generate .”
• They seek to forward understanding. In other words, literature reviews examine and link together evidence described and validated in the research of others so a reader can learn how a field is developing. ( Research seems to agree that nature sounds can relieve stress and fatigue–this review will examine that conclusion so readers can understand/ build on how and why.)

Moving from the beginning to the very end of the literature review, we can also learn many things about literature reviews from the sources used. Think of each text listed in the References section of a literature review as contributing pieces to a gigantic puzzle.

Example 3.2: Look at the first three articles listed in the References for the article excerpted above:

Abbott, L. C., Taff, D., Newman, P., Benfield, J. A., and Mowen, A. J. (2016). The influence of natural sounds on attention restoration. J. Park Recreation Adm. 34, 5–15. doi: 10.18666/JPRA-2016-V34-I3-6893

Aletta, F., and Kang, J. (2019). Promoting healthy and supportive acoustic environments: going beyond the quietness. Int. J. Environ. Res. Public Health 16:4988. doi: 10.3390/ijerph16244988

Aletta, F., Oberman, T., and Kang, J. (2018). Associations between positive health-related effects and soundscapes perceptual constructs: a systematic review. Int. J. Environ. Res. Public Health 15:2392. doi: 10.3390/ijerph15112392

None of these sources are exactly the same. One focuses on sound and attention, the next two on sound and health, and none of them are quite the same as sound and restoration —but they are all pieces of the puzzle that give a full understanding of how sound and restorative environments relate.

As the author of the literature review, it is your job to join the pieces together, giving your reader a complete picture of what researchers know about your topic.

Literature reviews are an indispensable tool for researchers. Instead of having to read dozens of articles on a topic, a researcher could instead read a literature review that synthesizes what is known and puts each piece of scholarship into conversation with the others. This could be not only quicker, but also more valuable.

Have you heard the saying that the whole is more than the sum of its parts? The knowledge constructed by a well-written literature review often outweighs the knowledge constructed by simply reading each article in the References section on its own because the author of a literature review processes and analyzes the information for the reader.

Literature reviews occur in two general forms—as a background section in a scholarly work or as a stand-alone genre in and of itself. In both situations, the basic purpose and structure of the literature review is similar: it is the length and the scope that varies. For example, consider the previous chapter, the Proposal. In most proposals, you will want to convince your audience that you are informed on the background of your topic—a literature review is how you would do that. Since a proposal is commonly a short text, you do not have the space to summarize every piece of research. You must select an important set and synthesize that information into a small section signaling your expertise.

On the other hand, consider a professional journal intended to keep its readers up to date on new technologies and findings in a specific field or career. New ideas and discoveries are emerging every day, and it can be difficult to stay on top of all of these new findings, understand how they fit together, and also keep track of your own career responsibilities! A magazine might hire an author to read all the new research on a specific topic and synthesize it into a single article, a state-of-the-art review, so that practitioners in a field can read a single 25-page article instead of 100 25-page articles.

More Resources 3.1: Literature Reviews

II. Rhetorical Considerations: Voice

Using the scholarship of other writers and researchers is one of the things that differentiates academic writing from other types of writing. Using others’ scholarship in a meaningful way that creates new knowledge without mischaracterizing the original findings takes effort, attention, and usually several rounds of revision and rewriting. One of the issues is voice , which refers to the attitude and tone of a text—think of it as what the text “sounds like” in your head as you read it. Voice is an important element of cohesion , or what some people think of as “flow.” Creating a consistent voice in the mind of your reader helps them fit all the information in a text together in the way the author intends. Check out this advice from APAstyle.org about academic style and voice.

Think back to your annotated bibliography and how you created your summaries. You probably used key terms from the original authors’ texts, but because you had to take whole articles and restate the meaning in a short paragraph, there wasn’t room to just repeat the words of the original author. So you had to write the summaries in your voice . If you used those key terms correctly and in ways similar to original authors, those key terms probably did not interfere with cohesiveness and voice. However, in the literature review, you have many more voices to synthesize than you did to summarize in the annotated bibliography. Maintaining a consistent and cohesive voice will be challenging. An important way to maintain voice is through paraphrasing, discussed later in this chapter.

More Resources 3.2: Transitions

Another important way to maintain cohesion is through the use of metadiscourse (see Chapter 2) and transitional phrases. See this link for the use and meaning of transitional phrases, sometimes called signposts .

III. The Literature Review Across the Disciplines

Example 3.3: Academic and Professional Examples

Structure of Literature Reviews

While the details vary across disciplines, all literature reviews tend to have similar basic structure. The introduction of a literature review informs the reader on the topic by defining key terms, citing key researchers or research periods in the field, and introducing the main focus of the review in a descriptive thesis statement. The introduction also explains the organization of the review. In a literature review, you organize your discussion of the research by topic or theme— not article or author. This is in direct contrast to the annotated bibliography, which is often the first step in the writing process for a literature review.

In the annotated bibliography, you organize your entries in alphabetical order by authors’ last names. Each annotation is directly connected to a single text. A literature review is connected to a collection of texts, and therefore must be organized in a way that reflects this.

Example 3.4: Let’s examine the full paragraph that the thesis statement we analyzed earlier came from:

A systematic review by Aletta et al. (2018) has identified links between positive urban soundscapes (which may also include nature sounds) and health and well-being, including stress recovery. Given the emphasis on nature w ithin restorative environments (see Hartig et al., 2014 ), the present narrative literature review focuses on evidence for positive psychological experiences of nature sounds and soundscapes specifically, and in particular how listening to these can generate perceptions and outcomes of restoration from stress and fatigue. This review has five key objectives, summarized in Figure 1 [in the article] . First, it explores literature regarding the impact of nature sounds on perceptions and experiences of wider natural environments. Second, it examines evidence regarding cognitive and affective appraisals of nature sounds and their contributions to overall perceptions of restorative environments. Third, literature regarding restorative outcomes in response to nature sounds is assessed. Fourth, the relevance of key restoration theories to this top ic is examined and areas where these theories are limited are identified. Fifth, a possible new theoretical area of interest—semantic associations with nature—is discussed and exemplified by recent acoustics research (Ratcliffe, 2021, emphasis added).

Notice how the thesis statement (in bold ) is followed by an explicit description of the five key objectives—which correspond to the titles (usually called headings ) of the five major sections of the body of the literature review. The introduction basically outlines the body of the literature review to make it easier for a researcher to find the specific information they are looking for. What follows each of these headings is an analysis and synthesis of the topic described in the heading—which is what we mean when we say a literature review is organized by topic.

Example 3.5: See how the body sections of a literature review synthesize research and evidence in relation to a focused topic. Read this example taken from a literature review in another discipline, nursing.

The introduction states that the review’s purpose is to understand the issues facing nurses in situations such as the COVID-19 pandemic. The researchers found several themes in the research that all contributed to nurses’ experiences. This paragraph describes one of those themes which the authors label “Professional collegiality”:

3.2.2. Professional collegiality

Professional camaraderie amongst nursing colleagues working during a pandemic was high (Ives et al., 2009, Kim, 2018, Liu a nd Liehr , 2009). Nurses acknowledged the importance of caring for their co-workers and in sharing the load. Some nurses associated the experience with working on a battlefield, whereby they worked together as a team protecting one another (Chung et al., 20 05, Kang et al., 2018, Liu and Liehr , 2009). Appreciation of their nursing colleagues was demonstrated through sharing their experiences, willingness to work together and encouraging a team spirit (Shih et al., 2007, Chung et al., 2005, Chiang et al., 2007 ). (Ratcliffe, 2021, p.4)

In this single paragraph, there are seven different research articles cited, and some of them are cited twice. There is no way to write a coherent paragraph summarizing seven different research articles at once—instead, the authors of this paragraph reviewed what the researchers said about collegiality, found where their findings pointed in the same direction, and put those connections into their own words. This is the importance of the review’s body section: it is here where you really dig into the content, meaning, and implications of the scholarship you are discussing.

The end of a literature review looks different from the one- or two-paragraph conclusion we are used to in other texts. The end is often made up of multiple sections, each with a slightly different purpose, although all are probably recognizable to you. A “Discussion” section is almost always present, where the author summarizes the most important findings of each section. In most cases, the “Discussion” section does not contain new information, but ties the different body sections together in ways that provide a deeper analysis.

The end of a literature review may also contain an “Implications for Future Research” or “Resolution” after the Discussion—sometimes this final section is even called “Conclusion.” What this last section looks like is often dependent upon the type of review you are writing, and whether the review is standing alone as a complete text or part of a larger project.

In any situation, across all disciplines, it is important to understand how your literature review is meant to inform the reader and what kind of review is appropriate for the context, in order to decide how you should structure the beginning and end of your review.

Types of Literature Reviews

There are different types of literature reviews, although in undergraduate study the Traditional or Narrative Review is most common. Narrative reviews are somewhat exploratory in their content—in a narrative review you are synthesizing the results of specific texts selected for their connection to your topic. Narrative reviews almost always end with a section describing areas for future research if they are a stand-alone text, or a section describing why the author’s research is so needed if part of a larger research article. The chart below outlines the key differences between three major literature review types. Notice that each type has a slightly different purpose. You might think about which type best fits your project as you read.

Table 3.1: Types of Literature Reviews

More Resources 3.3: Literature Review Structures

IV. Research Strategies: Developing a Methodology

Systematic and scoping reviews should always contain a Research Methodology that explains to your reader exactly how you found the research you are reviewing. Often Narrative Reviews will also contain a research methodology, although it will be slightly different since they are not comprehensive reviews, meaning, they do not attempt to find all the research on a topic—by design, they cover only a specific portion. Even if you are not required to write up your methodology, you need clear research strategies to find the appropriate scholarship for your literature review.

Example 3.6: Check out this excerpt from the methods sections from a psychology literature review. Note how the authors clearly describe what types of sources they’ll be using as well as their steps throughout the research process.

Drawing on individual case studies, archival reports, correlational studies, and laboratory and field experiments, this monograph scrutinizes a sequence of events during which confessions may be obtained from criminal suspects and used as evidence. First, we examine the pre-interrogation interview, a process by which police …( Kassin and Gudjonsson , 2004, p.33)

Example 3.7: Here is another example from the field of education. In it the authors describe two separate searches they performed to gather the literature—the first search used key terms they decided upon before reading any scholarship, and the second search used the terms that they found were common to that first set of texts (see more about key terms here and in the Annotated Bibliography chapter).

We conducted two rounds of literature searches, utilizing the following databases: World CAT (general search), EB SCO Academic Search Complete, EBSCO Education Source, and Linguistics and Language Behavior Abstracts (ProQuest). In the first round, we searched using every possible combination of the following terms: ‘race,’ ‘language teaching,’ ‘ethnicity,’ ‘language p edagogy,’ ‘Whiteness,’ ‘racialized,’ ‘antiracism,’ and ‘ nativeness .’ For the second round of our literature search, we searched using terms that we saw emerging from the literature such as ‘racial identities of language learners,’ ‘racial identities of lan guage teachers,’ ‘language varieties and language teaching,’ ‘race and language teacher education,’ ‘race and educational policy,’ ‘race and language programs,’ and ‘race and language curriculum’ and also repeated our earlier searches in order to keep the literature updated. (Von Esch et al., 2020, p. 392)

No matter the type of research (see a description of qualitative vs. quantitative research ), the specific genres (see descriptions of academic research genres ), or the time frame (see a discussion on the importance of publication date ) you use for your review, it is important to think through the options, make a decision, and incorporate all your research knowledge—use of key terms, use of subject filters, use of specialized databases, etc.—into a coherent and meaningful process that results in the best scholarship for your inquiry and review.

Here’s a video to help you get started on using databases for research:

Library Referral: Connecting the Conversation with Scholarly Sources and Beyond​

(by Annie R. Armstrong)

Research involves drawing from numerous voices from a range of source types. The sources you choose to include in your conversation are context-specific and might vary depending on your topic or the parameters of your assignment. Review your assignment description and talk to your instructor about guidelines. While most research papers emphasize scholarly sources, expertise isn’t always equated with scholarliness and you might want to branch out. For example, a research paper focusing on exploitation of Native American land and communities by the mining industry should make some attempt to include sources generated by the communities under discussion, especially if their point of view is not represented in the peer-reviewed, scholarly sources you’ve found. Think about who the stakeholders are as related to various aspects of your topic and how you can tap into their voices through available resources. You may want to consult a librarian about this.

The chart below summarizes the breadth of source types available through library websites versus the open web:

Table 3.2: Scholarly Sources and Beyond

V. Reading Strategies: Intertextuality and Graphic Organizers

Typically we think of reading as something we do to learn the content of a text—and this is absolutely true! But true understanding means knowing the relationships between and impact of separate but related topics, which might mean understanding how different texts—generally focused on one topic—overlap or differ.

Intertextuality refers to the connections that exist between texts. Intertextuality as a reading strategy means looking for the connections between the text you are reading and others you have already read; anticipating connections with other texts that you have not yet read, but plan to; as well as connections to whole disciplines, fields, and social phenomena. Reading for intertextuality means looking for opportunities to connect texts with each other, and keeping track of those connections in a productive way.

This means note-taking is essential to intertextual reading. Once you have thought carefully about why you are reading a text, what types of information to look for, and what you will do with that information, you can better decide how to keep track of that information. In regards to literature reviews, one type of graphic organizer dominates: the Synthesis Matrix.

The synthesis matrix is a way to keep track of the themes, concepts, and patterns that are emerging from your reading—NOT all the individual content of each article. This is important, yes, and you will need the citations, but literature reviews move one step further into the topic than simply identifying the pieces. You will need to synthesize.

If you have an annotated bibliography of sources already, it is the perfect way to start your synthesis matrix. An annotated bibliography is often the first step in preparing for a literature review, and is quite similar to an ingredient list, if we are using the metaphor from the introduction. (For a detailed description of how to write an annotated bibliography, see Chapter 1 ).

In your annotations, you will have selected the most important information that text supplies in relation to your topic. For an example, let’s take the Conference on College Composition and Communication’s statement “ Students’ Right to Their Own Language ,” which contains two annotated bibliographies. The second uses more recent sources and looks most like the annotated bibliographies you will write as a student, so let’s start there.

Example 3.8: Here are three annotations from that bibliography. As you read, take notice of the different highlighted colors. Phrases italicized and highlighted green identify ideas related to linguistic identity , phrases bolded and highlighted in blue identify concepts related to grammar analysis , and phrases underlined and highlighted orange identify groups and ideas related to educational objectives :

Fought, Carmen. Chicano English in Context. New York: Palgrave Macmillan, 2003.

Based primarily on data collected from adolescent and young adult native speakers in Los Angeles , this book is a comprehensive sociolinguistic study of language and language change in Latino/a communities. It provides the basics of Chicano English (CE) structure (phonology, syntax, and semantics) and its connection to the social and cultural identity of its speakers, along with detailed analyses of particular sociolinguistic variables. Emphasis is given to the historical, social, and linguistic contexts of CE. In addition, the differences between native and non-native CE speakers are covered. A final chapter discusses the future of research on CE.

Lippi-Green, Rosina. English with an Accent: Language, Ideology, and Discrimination in the United States . London and New York: Routledge, 1997.

The author examines linguistic facts about the structure and function of language , explores commonly held myths about language, and develops a model of “the language subordination process.” Then, using a case-study approach, she applies the model to specific institutional practices (e.g., in education, news media, business) to show how false assumptions about language lead to language subordination. The author analyzes specific groups and individuals (speakers of African American English, Southern U.S. English, and the foreign-language accent of Latinos and Asian Americans) and discusses why and how some embrace linguistic assimilation while others resist it.

Nero, Shondel J. Englishes in Contact: Anglophone Caribbean Students in an Urban College. Cresskill, NJ: Hampton Press, 2001.

This qualitative study of four anglophone Caribbean students at a New York City college offers an in-depth examination of the students’ written and spoken language and the challenges faced by both students and teachers as such students acquire academic literacy. Case studies of the four participants include excerpts from tape-recorded interviews, which reflect their linguistic self-perception, and sociolinguistic and educational experiences in their home countries and in New York City. Samples of their college writing over four semesters are represented and analyzed on morphosyntactic and discourse levels to determine the patterns that emerge when Creole English speakers attempt to write Standard Written English. Related issues such as language and identity , language attitudes, and educational responses to ethnolinguistic diversity are also discussed.

Once you have identified a concept like “language and identity” for your literature review, you can start getting “intertextual”! Review your other annotated sources and your new sources for their discussion of language and identity, as well as parallel concepts—what else do researchers address when they discuss language and identity? What do they discuss instead? Go back to the methods you used to come up with key terms for your literature search—the same strategies now apply to your reading. Also look for “umbrella” concepts, patterns in methodologies—anything that emerges while you read intertextually, focusing on the text in front of you while also remembering all the others you read before. Look for the themes in your annotated bibliography and keep track of the page numbers where these themes appear—plan to go back to those pages several times as you write your literature review.

This is a different type of reading than you did for the annotated bibliography, and might mean you go back and reread your sources several times in this new way—don’t think of this as just repeating labor you have already performed. This is new work, designed to uncover new things in the research. Re-reading articles multiple times is something all serious writers do, and something you should do, too. It isn’t redundant, it is recur sive .

Table 3.3: Synthesis Matrix for Individuals’ Choices in Linguistic Identity

Put your sources into conversations around your themes, as shown in the table above. Notice that the top row names the themes covered in that column, put into original wording similar, but not identical, to the wording in the annotated bibliographies. Not every source will address every topic—not every article is the same. The last row starts to describe what is happening in each column across the whole collection of texts. In this way, your synthesis matrix takes the ingredient list provided by the annotated bibliography and makes it into a recipe for your final product—the literature review.

More Resources 3.4: Synthesis Matrix

VI. Writing Strategies: Citation, Quotation, and Paraphrase

Citation is when you use the work of other authors in your writing and mark that portion of your writing so your reader understands what idea is being “borrowed.” Citation also tells your reader where they could find that original idea in the original text, and how your text fits together with the web of other texts related to your topic: in other words, citations help create intertextuality. A citation placed in your sentences should refer directly to the full bibliographic information in your Works Cited or References page.

As you read in Chapter 1, there are different styles of citation including AMA, APA, CMS, and MLA. You can refer back to that chapter for a more detailed explanation of each. In this section, we’ll cover the basics that are common to citation practices. Most academic styles use the original author’s last name as the central part of the in-text citation, since References pages usually list cited works alphabetically by last name, but some use footnotes or endnotes instead, listing works in the order they were cited. It is important to know which academic style you are using for your literature review so that you can make the right choice.

In-text citation takes one of two forms: parenthetical or narrative. In a narrative citation the author of the original work is mentioned in the sentence.

Example 3.9: Here’s an example taken from the introduction of the same literature review discussed in the Research Strategies: Developing a Methodology section of this chapter.

Several pieces offered a comprehensive review of the historical literature on the formation of Black English as a construct in the context of slavery and Jim Crow, and the historical teaching of Black English within the U .S. context, including Wheeler ( 2016 ) and Alim and Baugh (2007). Wheeler (2016) equated Standard English with ‘White’ English and challenged its hegemony in dialectically diverse classrooms. She named the “racism inherent in [fostering] bidialectalism [th rough teaching]” (p. 380), arguing that we are acknowledging that the only way for African-Americans to be upwardly mobile was to learn how to speak ‘White’ English. Alim (2010) , explained, “By uncritically presenting language varieties as ‘equal’ but diff ering in levels of ‘appropriateness,’ language and Dialect Awareness programs run the risk of silently legitimizing ‘Standard English’” (p. 215)…. Current work addressing AAVE studies has been shifting focus to translingualism and to promoting such pedag ogies as code-meshing (Young, Barrett, Young Rivera and Lovejoy, 2014) and translanguaging (García & Wei, García and Wei, 2014) , embedded in a critical analysis of the racial logics underpinning the denigration of some languages. This work, combined with e xtensive examinations of the connections between race, language, teaching, and identity ( e.g. Flores & Rosa, 2015; Alim et al., 2016 ), has laid a foundation for a raciolinguistics approach to teaching, which we return to later in this article. (Von Esch et al., 2020, p. 399, emphasis added .)

In the first sentence, we see two narrative citations just before the period. These citations state the authors’ names as a part of the sentence, and put the publication date of the articles in parenthesis. It makes sense to use a narrative citation in the topic sentence, since most of the paragraph is a synthesis of Wheeler and Alim’s research. The second sentence starts with Wheeler’s name in the subject position, and the fourth sentence starts with Alim’s name in the subject position—both are narrative citations, a form chosen by the author to emphasize the importance and similarities in the two articles.

In the last two sentences, we see parenthetical citations. The citation information is in parenthesis within the sentences, which focuses the reader on the ideas, not the research itself. Imagine you were reading this article out loud—you would most certainly say the narrative citations “Wheeler” and “Alim”; you might choose not to say “Young, Barrett, Young-Rivera, & Lovejoy, 2014,” though, and no one listening to you would notice the omission. This is the most important difference between narrative and parenthetical citation—narrative draws attention to the researchers, while parenthetical allows a focus on ideas. In academic writing, you often have reason to use both, but it is important to note that using parenthetical citation is less disruptive to your voice—it keeps a reader focused on the ideas you are explaining.

Usually you are citing a type of quotation in your text (although different disciplines have other situations that they cite). Direct quotation and paraphrase are usually what we talk about when we talk about using resources in your writing, although summary is cited as well.

Direct quotation is when you take the original words of one author and place them in your own text. When you quote in your own writing, you mark the copied text—usually with quotation marks “” around the text and a citation afterwards. Quoting is useful when the original author is an important authority on a topic or if you want to define/describe another’s point of view in a way that leaves no room for misinterpretation.

In a literature review, a direct quote will almost always be accompanied by a narrative citation. But direct quoting can cause some issues in your own text, such as a sudden shift in voice and a loss of cohesion; the potential for misunderstanding and misrepresentation, since the quote has been separated from its original context; and wordiness —quotes can take up too much space both in terms of the quote itself, and of the explanation and context you must provide for the introduced idea. For these reasons, literature reviews do not contain much direct quoting.

Paraphrasing is a way to accomplish similar goals to direct quoting without causing the same problems. Paraphrasing is when you use only the original author’s key terms and ideas, but your own words. Paraphrasing still contains a citation afterwards that directs the reader to the full bibliographic information in your Works Cited, but does not require quotation marks since the language is yours. Paraphrase may be longer or shorter than the original author’s text, and uses both narrative and parenthetical citation. Paraphrase also allows you to cite more than one piece of research containing the same idea in a single sentence, such as the last sentence in the example paragraph above. This kind of citation string is important to literature reviews because it clearly identifies patterns and trends in research findings.

Key Takeaways

• Literature reviews are a synthesis of what other researchers have discovered on your topic. Think of reviews as “the big picture.”
• Taking so much information from other sources can get confusing–use section headings to keep your review organized and clear.
• Diverse citation, quotation, and paraphrasing techniques are necessary to help your reader understand where the ideas are coming from, AND to help make the ideas “stick together.”
• Keeping all the new knowledge you are learning from your sources organized is hard! Take notes using citations and use a graphic organizer to keep yourself on track.

Fernandez, Lord, H., Halcomb, E., Moxham, L., Middleton, R., Alananzeh, I., & Ellwood, L. (2020). Implications for COVID-19: A systematic review of nurses’ experiences of working in acute care hospital settings during a respiratory pandemic. International Journal of Nursing Studies , 111. https://doi.org/10.1016/j.ijnurstu.2020.103637

Kassin, S. M., & Gudjonsson, G. H. (2004). The psychology of confessions. Psychological Science in the Public Interest , 5 (2), 33–67. https://doi.org/10.1111/j.1529-1006.2004.00016.x

National Council of Teachers of English. (2018, June 16). Students’ right to their own language (with bibliography) . Conference on College Composition and Communication. Retrieved July 24, 2022, from https://cccc.ncte.org/cccc/resources/positions/srtolsummary

NEIU Libraries. (2020). “How should I search in a database?”  YouTube . https://www.youtube.com/watch?v=8fgBF0EuH_o

Ratcliffe, E. (2021). Summary Flowchart [Image]. Frontiers in Psychology. https://www.frontiersin.org/articles/10.3389/fpsyg.2021.570563/full#B3

Ratcliffe, E. (2021). Sound and soundscape in restorative natural environments: A narrative literature review. Frontiers in Psychology , 12 . https://doi.org/10.3389/fpsyg.2021.570563

Sasaki. K. (2022). Synthesis and Recipes [Image].

Von Esch, K., Motha, S., & Kubota, R. (2020). Race and language teaching. Language Teaching, 53 (4), 391-421. doi:10.1017/S0261444820000269

Writing for Inquiry and Research Copyright © 2023 by Charitianne Williams is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License , except where otherwise noted.

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Neal Haddaway

October 19th, 2020, 8 common problems with literature reviews and how to fix them.

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Estimated reading time: 5 minutes

Literature reviews are an integral part of the process and communication of scientific research. Whilst systematic reviews have become regarded as the highest standard of evidence synthesis, many literature reviews fall short of these standards and may end up presenting biased or incorrect conclusions. In this post, Neal Haddaway highlights 8 common problems with literature review methods, provides examples for each and provides practical solutions for ways to mitigate them.

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Researchers regularly review the literature – it’s an integral part of day-to-day research: finding relevant research, reading and digesting the main findings, summarising across papers, and making conclusions about the evidence base as a whole. However, there is a fundamental difference between brief, narrative approaches to summarising a selection of studies and attempting to reliably and comprehensively summarise an evidence base to support decision-making in policy and practice.

So-called ‘evidence-informed decision-making’ (EIDM) relies on rigorous systematic approaches to synthesising the evidence. Systematic review has become the highest standard of evidence synthesis and is well established in the pipeline from research to practice in the field of health . Systematic reviews must include a suite of specifically designed methods for the conduct and reporting of all synthesis activities (planning, searching, screening, appraising, extracting data, qualitative/quantitative/mixed methods synthesis, writing; e.g. see the Cochrane Handbook ). The method has been widely adapted into other fields, including environment (the Collaboration for Environmental Evidence ) and social policy (the Campbell Collaboration ).

Despite the growing interest in systematic reviews, traditional approaches to reviewing the literature continue to persist in contemporary publications across disciplines. These reviews, some of which are incorrectly referred to as ‘systematic’ reviews, may be susceptible to bias and as a result, may end up providing incorrect conclusions. This is of particular concern when reviews address key policy- and practice- relevant questions, such as the ongoing COVID-19 pandemic or climate change.

These limitations with traditional literature review approaches could be improved relatively easily with a few key procedures; some of them not prohibitively costly in terms of skill, time or resources.

In our recent paper in Nature Ecology and Evolution , we highlight 8 common problems with traditional literature review methods, provide examples for each from the field of environmental management and ecology, and provide practical solutions for ways to mitigate them.

There is a lack of awareness and appreciation of the methods needed to ensure systematic reviews are as free from bias and as reliable as possible: demonstrated by recent, flawed, high-profile reviews. We call on review authors to conduct more rigorous reviews, on editors and peer-reviewers to gate-keep more strictly, and the community of methodologists to better support the broader research community. Only by working together can we build and maintain a strong system of rigorous, evidence-informed decision-making in conservation and environmental management.

Note: This article gives the views of the authors, and not the position of the LSE Impact Blog, nor of the London School of Economics. Please review our  comments policy  if you have any concerns on posting a comment below

Image credit:  Jaeyoung Geoffrey Kang  via unsplash

About the author

Neal Haddaway is a Senior Research Fellow at the Stockholm Environment Institute, a Humboldt Research Fellow at the Mercator Research Institute on Global Commons and Climate Change, and a Research Associate at the Africa Centre for Evidence. He researches evidence synthesis methodology and conducts systematic reviews and maps in the field of sustainability and environmental science. His main research interests focus on improving the transparency, efficiency and reliability of evidence synthesis as a methodology and supporting evidence synthesis in resource constrained contexts. He co-founded and coordinates the Evidence Synthesis Hackathon (www.eshackathon.org) and is the leader of the Collaboration for Environmental Evidence centre at SEI. @nealhaddaway

Why is mission creep a problem and not a legitimate response to an unexpected finding in the literature? Surely the crucial points are that the review’s scope is stated clearly and implemented rigorously, not when the scope was finalised.

• Pingback: Quick, but not dirty – Can rapid evidence reviews reliably inform policy? | Impact of Social Sciences

#9. Most of them are terribly boring. Which is why I teach students how to make them engaging…and useful.

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New Comprehensive Review Examines Potential Harms of COVID-19 Vaccination and Intramuscular Vaccination

WASHINGTON — A  new report from the National Academies of Sciences, Engineering, and Medicine reviews evidence for 19 potential harms of the COVID-19 vaccines, and for nine potential shoulder injuries from intramuscular administration of vaccines more broadly. The committee that conducted the review identified sufficient evidence to draw 20 conclusions about whether these vaccines could cause specific harms, and drew 65 conclusions where it did not find enough evidence to establish, accept, or reject a causal relationship .

The Health Resources and Services Administration requested that the National Academies convene a committee to review the evidence regarding specific potential harms related to the COVID-19 vaccines used in the United States, for which HRSA had received claims for compensation under its Countermeasures Injury Compensation Program (CICP).

As part of “Operation Warp Speed,” a rapid response by the federal government to speed vaccine development during the COVID-19 pandemic, four vaccines were developed and authorized for emergency use in the U.S., with some now fully approved by the Food and Drug Administration. COVID-19 vaccines are estimated to have prevented 14.4 million deaths worldwide in the first year they were available.

COVID-19 Vaccines and Possible Harms

The report concludes that two messenger ribonucleic acid (mRNA) vaccines, manufactured by Pfizer-BioNTech and Moderna, can cause myocarditis — inflammation of the heart muscle. Evidence suggests the two mRNA vaccines do not cause infertility, Guillain-Barré syndrome, Bell’s palsy, thrombosis with thrombocytopenia syndrome (TTS), or myocardial infarction (heart attack). Evidence also suggests the Pfizer-BioNTech vaccine does not cause ischemic stroke.

Although there are a limited number of published studies on the Janssen vaccine, reflecting its limited use in the U.S., evidence suggests this vaccine may cause TTS and Guillain-Barré syndrome.

The report says that for all conclusions that do not establish a causal link, future studies that estimate effects more precisely or that better minimize bias and confounding variables could lead to a different finding.

“Despite a large body of evidence from extraordinary efforts by investigators around the world, our committee found that in many cases, if not most, evidence was insufficient to accept or reject causality for a particular potential harm from a specific COVID-19 vaccine,” said committee vice chair Anne Bass, professor of clinical medicine, Weill Cornell Medicine, and a rheumatologist at the Hospital for Special Surgery and New York Presbyterian Hospital. “In other cases, we did find sufficient evidence to favor rejection, favor acceptance, or establish causality. It is important to note, however, that identifying a harm does not mean that it occurs frequently. Harms associated with vaccines are rare.”

Shoulder Injuries and Possible Harms

HRSA also requested that the committee review the evidence regarding any vaccine administration — not specifically COVID-19 vaccines — and shoulder injuries , to help its National Vaccine Injury Compensation Program (VICP) better understand whether vaccination can cause very specific types of shoulder injuries or a more general syndrome that it designated as “Shoulder Injuries Related to Vaccine Administration.” The report says that evidence shows vaccination may cause four specific shoulder injuries: acute subacromial/subdeltoid bursitis caused by direct injection of a vaccine into the bursa; acute rotator cuff tendinopathy caused by direct injection into or adjacent to a tendon; bone injury caused by direct injection into or adjacent to bone; and axial or radial nerve injury due to direct injection into or adjacent to the nerve. In addition, evidence suggests that intramuscular vaccine administration does not cause chronic rotator cuff disease.

Evidence in Children

Because potential vaccine-associated harms may differ in children and adults, the committee conducted an in-depth review of literature on adverse events related to COVID-19 vaccines in children under 18, and found insufficient evidence to make conclusions specific to children. At the time of the committee’s review, data on children were only available for the Pfizer-BioNTech and Moderna vaccines, due to later authorization of COVID-19 vaccines for emergency use in children, and decreased uptake of COVID-19 vaccines in children, particularly those younger than 11. Ongoing and future pharmacovigilance and epidemiology studies should produce more definitive data on the risk and relative incidence of harms of COVID-19 vaccines in children.

About This Study

The report says all conclusions must be assessed in the context of the established harms of COVID-19 infection and the well-documented benefits of COVID-19 vaccines in preventing infection. The committee was not tasked with estimating the magnitude or strength of associations between vaccinations and outcomes, and did not offer conclusions regarding specific patient cases or whether VICP or CICP should award compensation in individual cases or in general.

“Given that the studies we reviewed were performed shortly after vaccines were available, the information in this report is a snapshot in time, and new vaccines will be developed and more research conducted,” said George Isham, senior fellow, HealthPartners Institute, and chair of the committee that wrote the report. “For example, the evidence does not address the real-world use of the COVID-19 vaccines in which many individuals received a ‘mix and match’ sequence of them. Many people vaccinated for COVID-19 also received other vaccines, such as influenza, simultaneously.”

The study — undertaken by the  Committee to Review Relevant Literature Regarding Adverse Effects Associated with Vaccines — was sponsored by the Health Resources and Services Administration of the U.S. Department of Health and Human Services.

The National Academies of Sciences, Engineering, and Medicine are private, nonprofit institutions that provide independent, objective analysis and advice to the nation to solve complex problems and inform public policy decisions related to science, engineering, and medicine. They operate under an 1863 congressional charter to the National Academy of Sciences, signed by President Lincoln.

Dana Korsen, Director of Media Relations Megan Lowry, Media Relations Manager Office of News and Public Information 202-334-2138; e-mail  [email protected]

Featured Publication

Evidence Review of the Adverse Effects of COVID-19 Vaccination and Intramuscular Vaccine Administration

Vaccines are a public health success story, as they have prevented or lessened the effects of many infectious diseases. To address concerns around potential vaccine injuries, the Health Resources and Services Administration (HRSA) administers the Vaccine Injury Compensation Program (VICP) and the Countermeasures Injury Compensation Program (CICP), which provide compensation to those who assert that they were injured by routine vaccines or medical countermeasures, respectively. The National Academies of Sciences, Engineering, and Medicine have contributed to the scientific basis for VICP compensation decisions for decades.

HRSA asked the National Academies to convene an expert committee to review the epidemiological, clinical, and biological evidence about the relationship between COVID-19 vaccines and specific adverse events, as well as intramuscular administration of vaccines and shoulder injuries. This report outlines the committee findings and conclusions.

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Lau F, Kuziemsky C, editors. Handbook of eHealth Evaluation: An Evidence-based Approach [Internet]. Victoria (BC): University of Victoria; 2017 Feb 27.

Handbook of eHealth Evaluation: An Evidence-based Approach [Internet].

Chapter 9 methods for literature reviews.

Guy Paré and Spyros Kitsiou .

9.1. Introduction

Literature reviews play a critical role in scholarship because science remains, first and foremost, a cumulative endeavour ( vom Brocke et al., 2009 ). As in any academic discipline, rigorous knowledge syntheses are becoming indispensable in keeping up with an exponentially growing eHealth literature, assisting practitioners, academics, and graduate students in finding, evaluating, and synthesizing the contents of many empirical and conceptual papers. Among other methods, literature reviews are essential for: (a) identifying what has been written on a subject or topic; (b) determining the extent to which a specific research area reveals any interpretable trends or patterns; (c) aggregating empirical findings related to a narrow research question to support evidence-based practice; (d) generating new frameworks and theories; and (e) identifying topics or questions requiring more investigation ( Paré, Trudel, Jaana, & Kitsiou, 2015 ).

Literature reviews can take two major forms. The most prevalent one is the “literature review” or “background” section within a journal paper or a chapter in a graduate thesis. This section synthesizes the extant literature and usually identifies the gaps in knowledge that the empirical study addresses ( Sylvester, Tate, & Johnstone, 2013 ). It may also provide a theoretical foundation for the proposed study, substantiate the presence of the research problem, justify the research as one that contributes something new to the cumulated knowledge, or validate the methods and approaches for the proposed study ( Hart, 1998 ; Levy & Ellis, 2006 ).

The second form of literature review, which is the focus of this chapter, constitutes an original and valuable work of research in and of itself ( Paré et al., 2015 ). Rather than providing a base for a researcher’s own work, it creates a solid starting point for all members of the community interested in a particular area or topic ( Mulrow, 1987 ). The so-called “review article” is a journal-length paper which has an overarching purpose to synthesize the literature in a field, without collecting or analyzing any primary data ( Green, Johnson, & Adams, 2006 ).

When appropriately conducted, review articles represent powerful information sources for practitioners looking for state-of-the art evidence to guide their decision-making and work practices ( Paré et al., 2015 ). Further, high-quality reviews become frequently cited pieces of work which researchers seek out as a first clear outline of the literature when undertaking empirical studies ( Cooper, 1988 ; Rowe, 2014 ). Scholars who track and gauge the impact of articles have found that review papers are cited and downloaded more often than any other type of published article ( Cronin, Ryan, & Coughlan, 2008 ; Montori, Wilczynski, Morgan, Haynes, & Hedges, 2003 ; Patsopoulos, Analatos, & Ioannidis, 2005 ). The reason for their popularity may be the fact that reading the review enables one to have an overview, if not a detailed knowledge of the area in question, as well as references to the most useful primary sources ( Cronin et al., 2008 ). Although they are not easy to conduct, the commitment to complete a review article provides a tremendous service to one’s academic community ( Paré et al., 2015 ; Petticrew & Roberts, 2006 ). Most, if not all, peer-reviewed journals in the fields of medical informatics publish review articles of some type.

The main objectives of this chapter are fourfold: (a) to provide an overview of the major steps and activities involved in conducting a stand-alone literature review; (b) to describe and contrast the different types of review articles that can contribute to the eHealth knowledge base; (c) to illustrate each review type with one or two examples from the eHealth literature; and (d) to provide a series of recommendations for prospective authors of review articles in this domain.

9.2. Overview of the Literature Review Process and Steps

As explained in Templier and Paré (2015) , there are six generic steps involved in conducting a review article:

• formulating the research question(s) and objective(s),
• searching the extant literature,
• screening for inclusion,
• assessing the quality of primary studies,
• extracting data, and
• analyzing data.

Although these steps are presented here in sequential order, one must keep in mind that the review process can be iterative and that many activities can be initiated during the planning stage and later refined during subsequent phases ( Finfgeld-Connett & Johnson, 2013 ; Kitchenham & Charters, 2007 ).

Formulating the research question(s) and objective(s): As a first step, members of the review team must appropriately justify the need for the review itself ( Petticrew & Roberts, 2006 ), identify the review’s main objective(s) ( Okoli & Schabram, 2010 ), and define the concepts or variables at the heart of their synthesis ( Cooper & Hedges, 2009 ; Webster & Watson, 2002 ). Importantly, they also need to articulate the research question(s) they propose to investigate ( Kitchenham & Charters, 2007 ). In this regard, we concur with Jesson, Matheson, and Lacey (2011) that clearly articulated research questions are key ingredients that guide the entire review methodology; they underscore the type of information that is needed, inform the search for and selection of relevant literature, and guide or orient the subsequent analysis. Searching the extant literature: The next step consists of searching the literature and making decisions about the suitability of material to be considered in the review ( Cooper, 1988 ). There exist three main coverage strategies. First, exhaustive coverage means an effort is made to be as comprehensive as possible in order to ensure that all relevant studies, published and unpublished, are included in the review and, thus, conclusions are based on this all-inclusive knowledge base. The second type of coverage consists of presenting materials that are representative of most other works in a given field or area. Often authors who adopt this strategy will search for relevant articles in a small number of top-tier journals in a field ( Paré et al., 2015 ). In the third strategy, the review team concentrates on prior works that have been central or pivotal to a particular topic. This may include empirical studies or conceptual papers that initiated a line of investigation, changed how problems or questions were framed, introduced new methods or concepts, or engendered important debate ( Cooper, 1988 ). Screening for inclusion: The following step consists of evaluating the applicability of the material identified in the preceding step ( Levy & Ellis, 2006 ; vom Brocke et al., 2009 ). Once a group of potential studies has been identified, members of the review team must screen them to determine their relevance ( Petticrew & Roberts, 2006 ). A set of predetermined rules provides a basis for including or excluding certain studies. This exercise requires a significant investment on the part of researchers, who must ensure enhanced objectivity and avoid biases or mistakes. As discussed later in this chapter, for certain types of reviews there must be at least two independent reviewers involved in the screening process and a procedure to resolve disagreements must also be in place ( Liberati et al., 2009 ; Shea et al., 2009 ). Assessing the quality of primary studies: In addition to screening material for inclusion, members of the review team may need to assess the scientific quality of the selected studies, that is, appraise the rigour of the research design and methods. Such formal assessment, which is usually conducted independently by at least two coders, helps members of the review team refine which studies to include in the final sample, determine whether or not the differences in quality may affect their conclusions, or guide how they analyze the data and interpret the findings ( Petticrew & Roberts, 2006 ). Ascribing quality scores to each primary study or considering through domain-based evaluations which study components have or have not been designed and executed appropriately makes it possible to reflect on the extent to which the selected study addresses possible biases and maximizes validity ( Shea et al., 2009 ). Extracting data: The following step involves gathering or extracting applicable information from each primary study included in the sample and deciding what is relevant to the problem of interest ( Cooper & Hedges, 2009 ). Indeed, the type of data that should be recorded mainly depends on the initial research questions ( Okoli & Schabram, 2010 ). However, important information may also be gathered about how, when, where and by whom the primary study was conducted, the research design and methods, or qualitative/quantitative results ( Cooper & Hedges, 2009 ). Analyzing and synthesizing data : As a final step, members of the review team must collate, summarize, aggregate, organize, and compare the evidence extracted from the included studies. The extracted data must be presented in a meaningful way that suggests a new contribution to the extant literature ( Jesson et al., 2011 ). Webster and Watson (2002) warn researchers that literature reviews should be much more than lists of papers and should provide a coherent lens to make sense of extant knowledge on a given topic. There exist several methods and techniques for synthesizing quantitative (e.g., frequency analysis, meta-analysis) and qualitative (e.g., grounded theory, narrative analysis, meta-ethnography) evidence ( Dixon-Woods, Agarwal, Jones, Young, & Sutton, 2005 ; Thomas & Harden, 2008 ).

9.3. Types of Review Articles and Brief Illustrations

EHealth researchers have at their disposal a number of approaches and methods for making sense out of existing literature, all with the purpose of casting current research findings into historical contexts or explaining contradictions that might exist among a set of primary research studies conducted on a particular topic. Our classification scheme is largely inspired from Paré and colleagues’ (2015) typology. Below we present and illustrate those review types that we feel are central to the growth and development of the eHealth domain.

9.3.1. Narrative Reviews

The narrative review is the “traditional” way of reviewing the extant literature and is skewed towards a qualitative interpretation of prior knowledge ( Sylvester et al., 2013 ). Put simply, a narrative review attempts to summarize or synthesize what has been written on a particular topic but does not seek generalization or cumulative knowledge from what is reviewed ( Davies, 2000 ; Green et al., 2006 ). Instead, the review team often undertakes the task of accumulating and synthesizing the literature to demonstrate the value of a particular point of view ( Baumeister & Leary, 1997 ). As such, reviewers may selectively ignore or limit the attention paid to certain studies in order to make a point. In this rather unsystematic approach, the selection of information from primary articles is subjective, lacks explicit criteria for inclusion and can lead to biased interpretations or inferences ( Green et al., 2006 ). There are several narrative reviews in the particular eHealth domain, as in all fields, which follow such an unstructured approach ( Silva et al., 2015 ; Paul et al., 2015 ).

Despite these criticisms, this type of review can be very useful in gathering together a volume of literature in a specific subject area and synthesizing it. As mentioned above, its primary purpose is to provide the reader with a comprehensive background for understanding current knowledge and highlighting the significance of new research ( Cronin et al., 2008 ). Faculty like to use narrative reviews in the classroom because they are often more up to date than textbooks, provide a single source for students to reference, and expose students to peer-reviewed literature ( Green et al., 2006 ). For researchers, narrative reviews can inspire research ideas by identifying gaps or inconsistencies in a body of knowledge, thus helping researchers to determine research questions or formulate hypotheses. Importantly, narrative reviews can also be used as educational articles to bring practitioners up to date with certain topics of issues ( Green et al., 2006 ).

Recently, there have been several efforts to introduce more rigour in narrative reviews that will elucidate common pitfalls and bring changes into their publication standards. Information systems researchers, among others, have contributed to advancing knowledge on how to structure a “traditional” review. For instance, Levy and Ellis (2006) proposed a generic framework for conducting such reviews. Their model follows the systematic data processing approach comprised of three steps, namely: (a) literature search and screening; (b) data extraction and analysis; and (c) writing the literature review. They provide detailed and very helpful instructions on how to conduct each step of the review process. As another methodological contribution, vom Brocke et al. (2009) offered a series of guidelines for conducting literature reviews, with a particular focus on how to search and extract the relevant body of knowledge. Last, Bandara, Miskon, and Fielt (2011) proposed a structured, predefined and tool-supported method to identify primary studies within a feasible scope, extract relevant content from identified articles, synthesize and analyze the findings, and effectively write and present the results of the literature review. We highly recommend that prospective authors of narrative reviews consult these useful sources before embarking on their work.

Darlow and Wen (2015) provide a good example of a highly structured narrative review in the eHealth field. These authors synthesized published articles that describe the development process of mobile health ( m-health ) interventions for patients’ cancer care self-management. As in most narrative reviews, the scope of the research questions being investigated is broad: (a) how development of these systems are carried out; (b) which methods are used to investigate these systems; and (c) what conclusions can be drawn as a result of the development of these systems. To provide clear answers to these questions, a literature search was conducted on six electronic databases and Google Scholar . The search was performed using several terms and free text words, combining them in an appropriate manner. Four inclusion and three exclusion criteria were utilized during the screening process. Both authors independently reviewed each of the identified articles to determine eligibility and extract study information. A flow diagram shows the number of studies identified, screened, and included or excluded at each stage of study selection. In terms of contributions, this review provides a series of practical recommendations for m-health intervention development.

9.3.2. Descriptive or Mapping Reviews

The primary goal of a descriptive review is to determine the extent to which a body of knowledge in a particular research topic reveals any interpretable pattern or trend with respect to pre-existing propositions, theories, methodologies or findings ( King & He, 2005 ; Paré et al., 2015 ). In contrast with narrative reviews, descriptive reviews follow a systematic and transparent procedure, including searching, screening and classifying studies ( Petersen, Vakkalanka, & Kuzniarz, 2015 ). Indeed, structured search methods are used to form a representative sample of a larger group of published works ( Paré et al., 2015 ). Further, authors of descriptive reviews extract from each study certain characteristics of interest, such as publication year, research methods, data collection techniques, and direction or strength of research outcomes (e.g., positive, negative, or non-significant) in the form of frequency analysis to produce quantitative results ( Sylvester et al., 2013 ). In essence, each study included in a descriptive review is treated as the unit of analysis and the published literature as a whole provides a database from which the authors attempt to identify any interpretable trends or draw overall conclusions about the merits of existing conceptualizations, propositions, methods or findings ( Paré et al., 2015 ). In doing so, a descriptive review may claim that its findings represent the state of the art in a particular domain ( King & He, 2005 ).

In the fields of health sciences and medical informatics, reviews that focus on examining the range, nature and evolution of a topic area are described by Anderson, Allen, Peckham, and Goodwin (2008) as mapping reviews . Like descriptive reviews, the research questions are generic and usually relate to publication patterns and trends. There is no preconceived plan to systematically review all of the literature although this can be done. Instead, researchers often present studies that are representative of most works published in a particular area and they consider a specific time frame to be mapped.

An example of this approach in the eHealth domain is offered by DeShazo, Lavallie, and Wolf (2009). The purpose of this descriptive or mapping review was to characterize publication trends in the medical informatics literature over a 20-year period (1987 to 2006). To achieve this ambitious objective, the authors performed a bibliometric analysis of medical informatics citations indexed in medline using publication trends, journal frequencies, impact factors, Medical Subject Headings (MeSH) term frequencies, and characteristics of citations. Findings revealed that there were over 77,000 medical informatics articles published during the covered period in numerous journals and that the average annual growth rate was 12%. The MeSH term analysis also suggested a strong interdisciplinary trend. Finally, average impact scores increased over time with two notable growth periods. Overall, patterns in research outputs that seem to characterize the historic trends and current components of the field of medical informatics suggest it may be a maturing discipline (DeShazo et al., 2009).

9.3.3. Scoping Reviews

Scoping reviews attempt to provide an initial indication of the potential size and nature of the extant literature on an emergent topic (Arksey & O’Malley, 2005; Daudt, van Mossel, & Scott, 2013 ; Levac, Colquhoun, & O’Brien, 2010). A scoping review may be conducted to examine the extent, range and nature of research activities in a particular area, determine the value of undertaking a full systematic review (discussed next), or identify research gaps in the extant literature ( Paré et al., 2015 ). In line with their main objective, scoping reviews usually conclude with the presentation of a detailed research agenda for future works along with potential implications for both practice and research.

Unlike narrative and descriptive reviews, the whole point of scoping the field is to be as comprehensive as possible, including grey literature (Arksey & O’Malley, 2005). Inclusion and exclusion criteria must be established to help researchers eliminate studies that are not aligned with the research questions. It is also recommended that at least two independent coders review abstracts yielded from the search strategy and then the full articles for study selection ( Daudt et al., 2013 ). The synthesized evidence from content or thematic analysis is relatively easy to present in tabular form (Arksey & O’Malley, 2005; Thomas & Harden, 2008 ).

One of the most highly cited scoping reviews in the eHealth domain was published by Archer, Fevrier-Thomas, Lokker, McKibbon, and Straus (2011) . These authors reviewed the existing literature on personal health record ( phr ) systems including design, functionality, implementation, applications, outcomes, and benefits. Seven databases were searched from 1985 to March 2010. Several search terms relating to phr s were used during this process. Two authors independently screened titles and abstracts to determine inclusion status. A second screen of full-text articles, again by two independent members of the research team, ensured that the studies described phr s. All in all, 130 articles met the criteria and their data were extracted manually into a database. The authors concluded that although there is a large amount of survey, observational, cohort/panel, and anecdotal evidence of phr benefits and satisfaction for patients, more research is needed to evaluate the results of phr implementations. Their in-depth analysis of the literature signalled that there is little solid evidence from randomized controlled trials or other studies through the use of phr s. Hence, they suggested that more research is needed that addresses the current lack of understanding of optimal functionality and usability of these systems, and how they can play a beneficial role in supporting patient self-management ( Archer et al., 2011 ).

9.3.4. Forms of Aggregative Reviews

Healthcare providers, practitioners, and policy-makers are nowadays overwhelmed with large volumes of information, including research-based evidence from numerous clinical trials and evaluation studies, assessing the effectiveness of health information technologies and interventions ( Ammenwerth & de Keizer, 2004 ; Deshazo et al., 2009 ). It is unrealistic to expect that all these disparate actors will have the time, skills, and necessary resources to identify the available evidence in the area of their expertise and consider it when making decisions. Systematic reviews that involve the rigorous application of scientific strategies aimed at limiting subjectivity and bias (i.e., systematic and random errors) can respond to this challenge.

Systematic reviews attempt to aggregate, appraise, and synthesize in a single source all empirical evidence that meet a set of previously specified eligibility criteria in order to answer a clearly formulated and often narrow research question on a particular topic of interest to support evidence-based practice ( Liberati et al., 2009 ). They adhere closely to explicit scientific principles ( Liberati et al., 2009 ) and rigorous methodological guidelines (Higgins & Green, 2008) aimed at reducing random and systematic errors that can lead to deviations from the truth in results or inferences. The use of explicit methods allows systematic reviews to aggregate a large body of research evidence, assess whether effects or relationships are in the same direction and of the same general magnitude, explain possible inconsistencies between study results, and determine the strength of the overall evidence for every outcome of interest based on the quality of included studies and the general consistency among them ( Cook, Mulrow, & Haynes, 1997 ). The main procedures of a systematic review involve:

• Formulating a review question and developing a search strategy based on explicit inclusion criteria for the identification of eligible studies (usually described in the context of a detailed review protocol).
• Searching for eligible studies using multiple databases and information sources, including grey literature sources, without any language restrictions.
• Selecting studies, extracting data, and assessing risk of bias in a duplicate manner using two independent reviewers to avoid random or systematic errors in the process.
• Analyzing data using quantitative or qualitative methods.
• Presenting results in summary of findings tables.
• Interpreting results and drawing conclusions.

Many systematic reviews, but not all, use statistical methods to combine the results of independent studies into a single quantitative estimate or summary effect size. Known as meta-analyses , these reviews use specific data extraction and statistical techniques (e.g., network, frequentist, or Bayesian meta-analyses) to calculate from each study by outcome of interest an effect size along with a confidence interval that reflects the degree of uncertainty behind the point estimate of effect ( Borenstein, Hedges, Higgins, & Rothstein, 2009 ; Deeks, Higgins, & Altman, 2008 ). Subsequently, they use fixed or random-effects analysis models to combine the results of the included studies, assess statistical heterogeneity, and calculate a weighted average of the effect estimates from the different studies, taking into account their sample sizes. The summary effect size is a value that reflects the average magnitude of the intervention effect for a particular outcome of interest or, more generally, the strength of a relationship between two variables across all studies included in the systematic review. By statistically combining data from multiple studies, meta-analyses can create more precise and reliable estimates of intervention effects than those derived from individual studies alone, when these are examined independently as discrete sources of information.

The review by Gurol-Urganci, de Jongh, Vodopivec-Jamsek, Atun, and Car (2013) on the effects of mobile phone messaging reminders for attendance at healthcare appointments is an illustrative example of a high-quality systematic review with meta-analysis. Missed appointments are a major cause of inefficiency in healthcare delivery with substantial monetary costs to health systems. These authors sought to assess whether mobile phone-based appointment reminders delivered through Short Message Service ( sms ) or Multimedia Messaging Service ( mms ) are effective in improving rates of patient attendance and reducing overall costs. To this end, they conducted a comprehensive search on multiple databases using highly sensitive search strategies without language or publication-type restrictions to identify all rct s that are eligible for inclusion. In order to minimize the risk of omitting eligible studies not captured by the original search, they supplemented all electronic searches with manual screening of trial registers and references contained in the included studies. Study selection, data extraction, and risk of bias assessments were performed inde­­pen­dently by two coders using standardized methods to ensure consistency and to eliminate potential errors. Findings from eight rct s involving 6,615 participants were pooled into meta-analyses to calculate the magnitude of effects that mobile text message reminders have on the rate of attendance at healthcare appointments compared to no reminders and phone call reminders.

Meta-analyses are regarded as powerful tools for deriving meaningful conclusions. However, there are situations in which it is neither reasonable nor appropriate to pool studies together using meta-analytic methods simply because there is extensive clinical heterogeneity between the included studies or variation in measurement tools, comparisons, or outcomes of interest. In these cases, systematic reviews can use qualitative synthesis methods such as vote counting, content analysis, classification schemes and tabulations, as an alternative approach to narratively synthesize the results of the independent studies included in the review. This form of review is known as qualitative systematic review.

A rigorous example of one such review in the eHealth domain is presented by Mickan, Atherton, Roberts, Heneghan, and Tilson (2014) on the use of handheld computers by healthcare professionals and their impact on access to information and clinical decision-making. In line with the methodological guide­lines for systematic reviews, these authors: (a) developed and registered with prospero ( www.crd.york.ac.uk/ prospero / ) an a priori review protocol; (b) conducted comprehensive searches for eligible studies using multiple databases and other supplementary strategies (e.g., forward searches); and (c) subsequently carried out study selection, data extraction, and risk of bias assessments in a duplicate manner to eliminate potential errors in the review process. Heterogeneity between the included studies in terms of reported outcomes and measures precluded the use of meta-analytic methods. To this end, the authors resorted to using narrative analysis and synthesis to describe the effectiveness of handheld computers on accessing information for clinical knowledge, adherence to safety and clinical quality guidelines, and diagnostic decision-making.

In recent years, the number of systematic reviews in the field of health informatics has increased considerably. Systematic reviews with discordant findings can cause great confusion and make it difficult for decision-makers to interpret the review-level evidence ( Moher, 2013 ). Therefore, there is a growing need for appraisal and synthesis of prior systematic reviews to ensure that decision-making is constantly informed by the best available accumulated evidence. Umbrella reviews , also known as overviews of systematic reviews, are tertiary types of evidence synthesis that aim to accomplish this; that is, they aim to compare and contrast findings from multiple systematic reviews and meta-analyses ( Becker & Oxman, 2008 ). Umbrella reviews generally adhere to the same principles and rigorous methodological guidelines used in systematic reviews. However, the unit of analysis in umbrella reviews is the systematic review rather than the primary study ( Becker & Oxman, 2008 ). Unlike systematic reviews that have a narrow focus of inquiry, umbrella reviews focus on broader research topics for which there are several potential interventions ( Smith, Devane, Begley, & Clarke, 2011 ). A recent umbrella review on the effects of home telemonitoring interventions for patients with heart failure critically appraised, compared, and synthesized evidence from 15 systematic reviews to investigate which types of home telemonitoring technologies and forms of interventions are more effective in reducing mortality and hospital admissions ( Kitsiou, Paré, & Jaana, 2015 ).

9.3.5. Realist Reviews

Realist reviews are theory-driven interpretative reviews developed to inform, enhance, or supplement conventional systematic reviews by making sense of heterogeneous evidence about complex interventions applied in diverse contexts in a way that informs policy decision-making ( Greenhalgh, Wong, Westhorp, & Pawson, 2011 ). They originated from criticisms of positivist systematic reviews which centre on their “simplistic” underlying assumptions ( Oates, 2011 ). As explained above, systematic reviews seek to identify causation. Such logic is appropriate for fields like medicine and education where findings of randomized controlled trials can be aggregated to see whether a new treatment or intervention does improve outcomes. However, many argue that it is not possible to establish such direct causal links between interventions and outcomes in fields such as social policy, management, and information systems where for any intervention there is unlikely to be a regular or consistent outcome ( Oates, 2011 ; Pawson, 2006 ; Rousseau, Manning, & Denyer, 2008 ).

To circumvent these limitations, Pawson, Greenhalgh, Harvey, and Walshe (2005) have proposed a new approach for synthesizing knowledge that seeks to unpack the mechanism of how “complex interventions” work in particular contexts. The basic research question — what works? — which is usually associated with systematic reviews changes to: what is it about this intervention that works, for whom, in what circumstances, in what respects and why? Realist reviews have no particular preference for either quantitative or qualitative evidence. As a theory-building approach, a realist review usually starts by articulating likely underlying mechanisms and then scrutinizes available evidence to find out whether and where these mechanisms are applicable ( Shepperd et al., 2009 ). Primary studies found in the extant literature are viewed as case studies which can test and modify the initial theories ( Rousseau et al., 2008 ).

The main objective pursued in the realist review conducted by Otte-Trojel, de Bont, Rundall, and van de Klundert (2014) was to examine how patient portals contribute to health service delivery and patient outcomes. The specific goals were to investigate how outcomes are produced and, most importantly, how variations in outcomes can be explained. The research team started with an exploratory review of background documents and research studies to identify ways in which patient portals may contribute to health service delivery and patient outcomes. The authors identified six main ways which represent “educated guesses” to be tested against the data in the evaluation studies. These studies were identified through a formal and systematic search in four databases between 2003 and 2013. Two members of the research team selected the articles using a pre-established list of inclusion and exclusion criteria and following a two-step procedure. The authors then extracted data from the selected articles and created several tables, one for each outcome category. They organized information to bring forward those mechanisms where patient portals contribute to outcomes and the variation in outcomes across different contexts.

9.3.6. Critical Reviews

Lastly, critical reviews aim to provide a critical evaluation and interpretive analysis of existing literature on a particular topic of interest to reveal strengths, weaknesses, contradictions, controversies, inconsistencies, and/or other important issues with respect to theories, hypotheses, research methods or results ( Baumeister & Leary, 1997 ; Kirkevold, 1997 ). Unlike other review types, critical reviews attempt to take a reflective account of the research that has been done in a particular area of interest, and assess its credibility by using appraisal instruments or critical interpretive methods. In this way, critical reviews attempt to constructively inform other scholars about the weaknesses of prior research and strengthen knowledge development by giving focus and direction to studies for further improvement ( Kirkevold, 1997 ).

Kitsiou, Paré, and Jaana (2013) provide an example of a critical review that assessed the methodological quality of prior systematic reviews of home telemonitoring studies for chronic patients. The authors conducted a comprehensive search on multiple databases to identify eligible reviews and subsequently used a validated instrument to conduct an in-depth quality appraisal. Results indicate that the majority of systematic reviews in this particular area suffer from important methodological flaws and biases that impair their internal validity and limit their usefulness for clinical and decision-making purposes. To this end, they provide a number of recommendations to strengthen knowledge development towards improving the design and execution of future reviews on home telemonitoring.

9.4. Summary

Table 9.1 outlines the main types of literature reviews that were described in the previous sub-sections and summarizes the main characteristics that distinguish one review type from another. It also includes key references to methodological guidelines and useful sources that can be used by eHealth scholars and researchers for planning and developing reviews.

Typology of Literature Reviews (adapted from Paré et al., 2015).

As shown in Table 9.1 , each review type addresses different kinds of research questions or objectives, which subsequently define and dictate the methods and approaches that need to be used to achieve the overarching goal(s) of the review. For example, in the case of narrative reviews, there is greater flexibility in searching and synthesizing articles ( Green et al., 2006 ). Researchers are often relatively free to use a diversity of approaches to search, identify, and select relevant scientific articles, describe their operational characteristics, present how the individual studies fit together, and formulate conclusions. On the other hand, systematic reviews are characterized by their high level of systematicity, rigour, and use of explicit methods, based on an “a priori” review plan that aims to minimize bias in the analysis and synthesis process (Higgins & Green, 2008). Some reviews are exploratory in nature (e.g., scoping/mapping reviews), whereas others may be conducted to discover patterns (e.g., descriptive reviews) or involve a synthesis approach that may include the critical analysis of prior research ( Paré et al., 2015 ). Hence, in order to select the most appropriate type of review, it is critical to know before embarking on a review project, why the research synthesis is conducted and what type of methods are best aligned with the pursued goals.

9.5. Concluding Remarks

In light of the increased use of evidence-based practice and research generating stronger evidence ( Grady et al., 2011 ; Lyden et al., 2013 ), review articles have become essential tools for summarizing, synthesizing, integrating or critically appraising prior knowledge in the eHealth field. As mentioned earlier, when rigorously conducted review articles represent powerful information sources for eHealth scholars and practitioners looking for state-of-the-art evidence. The typology of literature reviews we used herein will allow eHealth researchers, graduate students and practitioners to gain a better understanding of the similarities and differences between review types.

We must stress that this classification scheme does not privilege any specific type of review as being of higher quality than another ( Paré et al., 2015 ). As explained above, each type of review has its own strengths and limitations. Having said that, we realize that the methodological rigour of any review — be it qualitative, quantitative or mixed — is a critical aspect that should be considered seriously by prospective authors. In the present context, the notion of rigour refers to the reliability and validity of the review process described in section 9.2. For one thing, reliability is related to the reproducibility of the review process and steps, which is facilitated by a comprehensive documentation of the literature search process, extraction, coding and analysis performed in the review. Whether the search is comprehensive or not, whether it involves a methodical approach for data extraction and synthesis or not, it is important that the review documents in an explicit and transparent manner the steps and approach that were used in the process of its development. Next, validity characterizes the degree to which the review process was conducted appropriately. It goes beyond documentation and reflects decisions related to the selection of the sources, the search terms used, the period of time covered, the articles selected in the search, and the application of backward and forward searches ( vom Brocke et al., 2009 ). In short, the rigour of any review article is reflected by the explicitness of its methods (i.e., transparency) and the soundness of the approach used. We refer those interested in the concepts of rigour and quality to the work of Templier and Paré (2015) which offers a detailed set of methodological guidelines for conducting and evaluating various types of review articles.

To conclude, our main objective in this chapter was to demystify the various types of literature reviews that are central to the continuous development of the eHealth field. It is our hope that our descriptive account will serve as a valuable source for those conducting, evaluating or using reviews in this important and growing domain.

• Ammenwerth E., de Keizer N. An inventory of evaluation studies of information technology in health care. Trends in evaluation research, 1982-2002. International Journal of Medical Informatics. 2004; 44 (1):44–56. [ PubMed : 15778794 ]
• Anderson S., Allen P., Peckham S., Goodwin N. Asking the right questions: scoping studies in the commissioning of research on the organisation and delivery of health services. Health Research Policy and Systems. 2008; 6 (7):1–12. [ PMC free article : PMC2500008 ] [ PubMed : 18613961 ] [ CrossRef ]
• Archer N., Fevrier-Thomas U., Lokker C., McKibbon K. A., Straus S.E. Personal health records: a scoping review. Journal of American Medical Informatics Association. 2011; 18 (4):515–522. [ PMC free article : PMC3128401 ] [ PubMed : 21672914 ]
• Arksey H., O’Malley L. Scoping studies: towards a methodological framework. International Journal of Social Research Methodology. 2005; 8 (1):19–32.
• A systematic, tool-supported method for conducting literature reviews in information systems. Paper presented at the Proceedings of the 19th European Conference on Information Systems ( ecis 2011); June 9 to 11; Helsinki, Finland. 2011.
• Baumeister R. F., Leary M.R. Writing narrative literature reviews. Review of General Psychology. 1997; 1 (3):311–320.
• Becker L. A., Oxman A.D. In: Cochrane handbook for systematic reviews of interventions. Higgins J. P. T., Green S., editors. Hoboken, nj : John Wiley & Sons, Ltd; 2008. Overviews of reviews; pp. 607–631.
• Borenstein M., Hedges L., Higgins J., Rothstein H. Introduction to meta-analysis. Hoboken, nj : John Wiley & Sons Inc; 2009.
• Cook D. J., Mulrow C. D., Haynes B. Systematic reviews: Synthesis of best evidence for clinical decisions. Annals of Internal Medicine. 1997; 126 (5):376–380. [ PubMed : 9054282 ]
• Cooper H., Hedges L.V. In: The handbook of research synthesis and meta-analysis. 2nd ed. Cooper H., Hedges L. V., Valentine J. C., editors. New York: Russell Sage Foundation; 2009. Research synthesis as a scientific process; pp. 3–17.
• Cooper H. M. Organizing knowledge syntheses: A taxonomy of literature reviews. Knowledge in Society. 1988; 1 (1):104–126.
• Cronin P., Ryan F., Coughlan M. Undertaking a literature review: a step-by-step approach. British Journal of Nursing. 2008; 17 (1):38–43. [ PubMed : 18399395 ]
• Darlow S., Wen K.Y. Development testing of mobile health interventions for cancer patient self-management: A review. Health Informatics Journal. 2015 (online before print). [ PubMed : 25916831 ] [ CrossRef ]
• Daudt H. M., van Mossel C., Scott S.J. Enhancing the scoping study methodology: a large, inter-professional team’s experience with Arksey and O’Malley’s framework. bmc Medical Research Methodology. 2013; 13 :48. [ PMC free article : PMC3614526 ] [ PubMed : 23522333 ] [ CrossRef ]
• Davies P. The relevance of systematic reviews to educational policy and practice. Oxford Review of Education. 2000; 26 (3-4):365–378.
• Deeks J. J., Higgins J. P. T., Altman D.G. In: Cochrane handbook for systematic reviews of interventions. Higgins J. P. T., Green S., editors. Hoboken, nj : John Wiley & Sons, Ltd; 2008. Analysing data and undertaking meta-analyses; pp. 243–296.
• Deshazo J. P., Lavallie D. L., Wolf F.M. Publication trends in the medical informatics literature: 20 years of “Medical Informatics” in mesh . bmc Medical Informatics and Decision Making. 2009; 9 :7. [ PMC free article : PMC2652453 ] [ PubMed : 19159472 ] [ CrossRef ]
• Dixon-Woods M., Agarwal S., Jones D., Young B., Sutton A. Synthesising qualitative and quantitative evidence: a review of possible methods. Journal of Health Services Research and Policy. 2005; 10 (1):45–53. [ PubMed : 15667704 ]
• Finfgeld-Connett D., Johnson E.D. Literature search strategies for conducting knowledge-building and theory-generating qualitative systematic reviews. Journal of Advanced Nursing. 2013; 69 (1):194–204. [ PMC free article : PMC3424349 ] [ PubMed : 22591030 ]
• Grady B., Myers K. M., Nelson E. L., Belz N., Bennett L., Carnahan L. … Guidelines Working Group. Evidence-based practice for telemental health. Telemedicine Journal and E Health. 2011; 17 (2):131–148. [ PubMed : 21385026 ]
• Green B. N., Johnson C. D., Adams A. Writing narrative literature reviews for peer-reviewed journals: secrets of the trade. Journal of Chiropractic Medicine. 2006; 5 (3):101–117. [ PMC free article : PMC2647067 ] [ PubMed : 19674681 ]
• Greenhalgh T., Wong G., Westhorp G., Pawson R. Protocol–realist and meta-narrative evidence synthesis: evolving standards ( rameses ). bmc Medical Research Methodology. 2011; 11 :115. [ PMC free article : PMC3173389 ] [ PubMed : 21843376 ]
• Gurol-Urganci I., de Jongh T., Vodopivec-Jamsek V., Atun R., Car J. Mobile phone messaging reminders for attendance at healthcare appointments. Cochrane Database System Review. 2013; 12 cd 007458. [ PMC free article : PMC6485985 ] [ PubMed : 24310741 ] [ CrossRef ]
• Hart C. Doing a literature review: Releasing the social science research imagination. London: SAGE Publications; 1998.
• Higgins J. P. T., Green S., editors. Cochrane handbook for systematic reviews of interventions: Cochrane book series. Hoboken, nj : Wiley-Blackwell; 2008.
• Jesson J., Matheson L., Lacey F.M. Doing your literature review: traditional and systematic techniques. Los Angeles & London: SAGE Publications; 2011.
• King W. R., He J. Understanding the role and methods of meta-analysis in IS research. Communications of the Association for Information Systems. 2005; 16 :1.
• Kirkevold M. Integrative nursing research — an important strategy to further the development of nursing science and nursing practice. Journal of Advanced Nursing. 1997; 25 (5):977–984. [ PubMed : 9147203 ]
• Kitchenham B., Charters S. ebse Technical Report Version 2.3. Keele & Durham. uk : Keele University & University of Durham; 2007. Guidelines for performing systematic literature reviews in software engineering.
• Kitsiou S., Paré G., Jaana M. Systematic reviews and meta-analyses of home telemonitoring interventions for patients with chronic diseases: a critical assessment of their methodological quality. Journal of Medical Internet Research. 2013; 15 (7):e150. [ PMC free article : PMC3785977 ] [ PubMed : 23880072 ]
• Kitsiou S., Paré G., Jaana M. Effects of home telemonitoring interventions on patients with chronic heart failure: an overview of systematic reviews. Journal of Medical Internet Research. 2015; 17 (3):e63. [ PMC free article : PMC4376138 ] [ PubMed : 25768664 ]
• Levac D., Colquhoun H., O’Brien K. K. Scoping studies: advancing the methodology. Implementation Science. 2010; 5 (1):69. [ PMC free article : PMC2954944 ] [ PubMed : 20854677 ]
• Levy Y., Ellis T.J. A systems approach to conduct an effective literature review in support of information systems research. Informing Science. 2006; 9 :181–211.
• Liberati A., Altman D. G., Tetzlaff J., Mulrow C., Gøtzsche P. C., Ioannidis J. P. A. et al. Moher D. The prisma statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: Explanation and elaboration. Annals of Internal Medicine. 2009; 151 (4):W-65. [ PubMed : 19622512 ]
• Lyden J. R., Zickmund S. L., Bhargava T. D., Bryce C. L., Conroy M. B., Fischer G. S. et al. McTigue K. M. Implementing health information technology in a patient-centered manner: Patient experiences with an online evidence-based lifestyle intervention. Journal for Healthcare Quality. 2013; 35 (5):47–57. [ PubMed : 24004039 ]
• Mickan S., Atherton H., Roberts N. W., Heneghan C., Tilson J.K. Use of handheld computers in clinical practice: a systematic review. bmc Medical Informatics and Decision Making. 2014; 14 :56. [ PMC free article : PMC4099138 ] [ PubMed : 24998515 ]
• Moher D. The problem of duplicate systematic reviews. British Medical Journal. 2013; 347 (5040) [ PubMed : 23945367 ] [ CrossRef ]
• Montori V. M., Wilczynski N. L., Morgan D., Haynes R. B., Hedges T. Systematic reviews: a cross-sectional study of location and citation counts. bmc Medicine. 2003; 1 :2. [ PMC free article : PMC281591 ] [ PubMed : 14633274 ]
• Mulrow C. D. The medical review article: state of the science. Annals of Internal Medicine. 1987; 106 (3):485–488. [ PubMed : 3813259 ] [ CrossRef ]
• Evidence-based information systems: A decade later. Proceedings of the European Conference on Information Systems ; 2011. Retrieved from http://aisel ​.aisnet.org/cgi/viewcontent ​.cgi?article ​=1221&context ​=ecis2011 .
• Okoli C., Schabram K. A guide to conducting a systematic literature review of information systems research. ssrn Electronic Journal. 2010
• Otte-Trojel T., de Bont A., Rundall T. G., van de Klundert J. How outcomes are achieved through patient portals: a realist review. Journal of American Medical Informatics Association. 2014; 21 (4):751–757. [ PMC free article : PMC4078283 ] [ PubMed : 24503882 ]
• Paré G., Trudel M.-C., Jaana M., Kitsiou S. Synthesizing information systems knowledge: A typology of literature reviews. Information & Management. 2015; 52 (2):183–199.
• Patsopoulos N. A., Analatos A. A., Ioannidis J.P. A. Relative citation impact of various study designs in the health sciences. Journal of the American Medical Association. 2005; 293 (19):2362–2366. [ PubMed : 15900006 ]
• Paul M. M., Greene C. M., Newton-Dame R., Thorpe L. E., Perlman S. E., McVeigh K. H., Gourevitch M.N. The state of population health surveillance using electronic health records: A narrative review. Population Health Management. 2015; 18 (3):209–216. [ PubMed : 25608033 ]
• Pawson R. Evidence-based policy: a realist perspective. London: SAGE Publications; 2006.
• Pawson R., Greenhalgh T., Harvey G., Walshe K. Realist review—a new method of systematic review designed for complex policy interventions. Journal of Health Services Research & Policy. 2005; 10 (Suppl 1):21–34. [ PubMed : 16053581 ]
• Petersen K., Vakkalanka S., Kuzniarz L. Guidelines for conducting systematic mapping studies in software engineering: An update. Information and Software Technology. 2015; 64 :1–18.
• Petticrew M., Roberts H. Systematic reviews in the social sciences: A practical guide. Malden, ma : Blackwell Publishing Co; 2006.
• Rousseau D. M., Manning J., Denyer D. Evidence in management and organizational science: Assembling the field’s full weight of scientific knowledge through syntheses. The Academy of Management Annals. 2008; 2 (1):475–515.
• Rowe F. What literature review is not: diversity, boundaries and recommendations. European Journal of Information Systems. 2014; 23 (3):241–255.
• Shea B. J., Hamel C., Wells G. A., Bouter L. M., Kristjansson E., Grimshaw J. et al. Boers M. amstar is a reliable and valid measurement tool to assess the methodological quality of systematic reviews. Journal of Clinical Epidemiology. 2009; 62 (10):1013–1020. [ PubMed : 19230606 ]
• Shepperd S., Lewin S., Straus S., Clarke M., Eccles M. P., Fitzpatrick R. et al. Sheikh A. Can we systematically review studies that evaluate complex interventions? PLoS Medicine. 2009; 6 (8):e1000086. [ PMC free article : PMC2717209 ] [ PubMed : 19668360 ]
• Silva B. M., Rodrigues J. J., de la Torre Díez I., López-Coronado M., Saleem K. Mobile-health: A review of current state in 2015. Journal of Biomedical Informatics. 2015; 56 :265–272. [ PubMed : 26071682 ]
• Smith V., Devane D., Begley C., Clarke M. Methodology in conducting a systematic review of systematic reviews of healthcare interventions. bmc Medical Research Methodology. 2011; 11 (1):15. [ PMC free article : PMC3039637 ] [ PubMed : 21291558 ]
• Sylvester A., Tate M., Johnstone D. Beyond synthesis: re-presenting heterogeneous research literature. Behaviour & Information Technology. 2013; 32 (12):1199–1215.
• Templier M., Paré G. A framework for guiding and evaluating literature reviews. Communications of the Association for Information Systems. 2015; 37 (6):112–137.
• Thomas J., Harden A. Methods for the thematic synthesis of qualitative research in systematic reviews. bmc Medical Research Methodology. 2008; 8 (1):45. [ PMC free article : PMC2478656 ] [ PubMed : 18616818 ]
• Reconstructing the giant: on the importance of rigour in documenting the literature search process. Paper presented at the Proceedings of the 17th European Conference on Information Systems ( ecis 2009); Verona, Italy. 2009.
• Webster J., Watson R.T. Analyzing the past to prepare for the future: Writing a literature review. Management Information Systems Quarterly. 2002; 26 (2):11.
• Whitlock E. P., Lin J. S., Chou R., Shekelle P., Robinson K.A. Using existing systematic reviews in complex systematic reviews. Annals of Internal Medicine. 2008; 148 (10):776–782. [ PubMed : 18490690 ]

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NR1H4 disease: rapidly progressing neonatal intrahepatic cholestasis and early death

• Zhong-Die Li 1 ,
• Yu-Chuan Li 1 ,
• Jing-Zhao 1 ,
• Jian-She Wang 1 &
• Xin-Bao Xie   ORCID: orcid.org/0000-0002-3692-7356 1  

Orphanet Journal of Rare Diseases volume  19 , Article number:  171 ( 2024 ) Cite this article

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Clinical studies on progressive familial intrahepatic cholestasis (PFIC) type 5 caused by mutations in NR1H4 are limited.

New patients with biallelic NR1H4 variants from our center and all patients from literature were retrospectively analyzed.

Three new patients were identified to be carrying five new variants. Liver phenotypes of our patients manifests as low-γ-glutamyl transferase cholestasis, liver failure and related complications. One patient underwent liver transplantation (LT) and survived, and two other patients died without LT. Nine other patients were collected through literature review. Twelve out of 13 patients showed neonatal jaundice, with the median age of onset being 7 days after birth. Reported clinical manifestations included cholestasis (13/13, 100%), elevated AFP (11/11, 100%), coagulopathy (11/11, 100%), hypoglycemia (9/13, 69%), failure to thrive (8/13, 62%), splenomegaly (7/13, 54%), hyperammonemia (7/13, 54%), and hepatomegaly (6/13, 46%). Six of 13 patients received LT at a median age of 6.2 months, and only one patient died of acute infection at one year after LT. Other 7 patients had no LT and died with a median age of 5 months (range 1.2-8). There were 8 patients with homozygous genotype and 5 patients with compound heterozygous genotype. In total, 13 different variants were detected, and 5 out of 12 single or multiple nucleotides variants were located in exon 5.

Conclusions

We identified three newly-diagnosed patients and five novel mutations. NR1H4 -related PFIC typically cause progressive disease and early death. LT may be the only lifesaving therapy leading to cure.

Progressive familial intrahepatic cholestasis (PFIC) is an ever-growing group of autosomal recessive liver disorders caused by defects in genes associated with bile secretion, bile salt and lipid transporters and regulators [ 1 , 2 ]. Disease-causing genes of PFIC were gradually revealed, including ATP8B1 , ABCB11 , ABCB4 , TJP2 , NR1H4 , and MYO5B (named PFIC1 to 6) [ 3 , 4 , 5 , 6 ]. NR1H4 gene (OMIM *603,826), located on 12q23.1, encodes the farnesoid X receptor (FXR), a bile acid (BA)-activated transcription factor, and plays an essential role in BA homeostasis [ 7 ]. Biallelic pathogenic variants in NR1H4 were first identified in low-γ-glutamyl transferase (GGT) cholestasis patients and termed as PFIC5 in 2016 4 . So far, only 10 patients with PFIC5 from six unrelated families have been reported, usually presenting as rapidly progressive liver failure, vitamin K independent coagulopathy, high alpha-fetoprotein (AFP) and ultimately required a liver transplant (LT) to save lives [ 4 , 8 , 9 , 10 ]. To assess phenotypic spectrum and clinical outcomes in NR1H4 -related PFIC, we studied our patients in detail and reviewed previously reported patients in the literature.

Our patients were all Chinese children referred to the Center for Pediatric Liver Disease, Children’s Hospital of Fudan University from February 2016 to March 2023. Genetic testing, either whole-exome sequencing or liver panel sequencing, was performed in patients after excluding other causes of liver diseases (including infection, drug exposure, autoimmune hepatitis, and biliary atresia) [ 11 ]. Cytomegalovirus infection was not excluded due to its high prevalence in Chinese infants. When other known inherited liver disorders were excluded, patients with two or biallelic NR1H4 pathogenic/likely pathogenic/uncertain significance (P/LP/US) variants were collected. P/LP/US variants were classified according to the American College of Medical Genetics (ACMG)/Association for Molecular Pathology (AMP) criteria [ 12 ].

Genetic analyses and in silico assessment of NR1H4 variants

We confirmed these variants by Sanger sequencing and confirmed parental origins when available. Assessment of variant pathogenicity were performed with seven in silico tools including MutationTaster ( http://www.mutationtaster.org/ ), Sorting Intolerant From Tolerant (SIFT, http://sift.jcvi.org ), Rare Exome Variant Ensemble Learner (REVEL, https://labworm.com/tool/revel ), MutPred ( http://mutpred.mutdb.org/ ), and Protein Variation Effect Analyzer (PROVEAN, http://provean.jcvi.org/index.php ). Two programs, SpliceAI ( https://spliceailookup.broadinstitute.org/ ) and varSEAK ( https://varseak.bio/ ), were used to evaluate the effect of variants on mRNA splicing. Default settings were used for all in silico tools.

Literature review

A comprehensive literature review of the current literature was performed on March 2023 by searching PubMed ( https://pubmed.ncbi.nlm.nih.gov/ ), CNKI ( https://www.cnki.net/ ), and Wan fang ( https://www.wanfangdata.com.cn/ ) databases using the keywords “ NR1H4 variants, progressive familial intrahepatic cholestasis 5, and PFIC5”.

Identification of biallelic NR1H4 variants in 3 new patients and in silico assessment

We identified 5 unique NR1H4 variants from 3 unrelated Chinese patients with low GGT intrahepatic cholestasis from our cohort. Among these, there were 3 missense variants, one nonsense variant, and one canonical splicing variant. All variants have not been previously reported in medical literatures (See Table  1 ). Three out of 5 variants were absent in gnomAD (c.505T > A/p. (Cys169Ser), c.1235T > C/p. (Leu412Pro), and c.1066 + 1G > A/p.?). The other two were present in gnomAD, with a population frequency of 0/1/251,458 (number of homozygotes/allele count/allele number) for the c.688 C > T/p. (Arg230Ter) variant and 0/1/31,410 (number of homozygotes/allele count/allele number) for the c.527G > A/p. (Arg176Gln) variant. MutationTaster predicted that the nonsense variant (c.688 C > T/p. (Arg230Ter)) may lead to nonsense-mediated mRNA decay (NMD). SpliceAI and varSEAK predicted that the canonical splicing variant (c.1066 + 1G > A/p.?) lead to loss of donor splice site, most likely leading to protein truncation. Three missense variants were predicted to be pathogenic by five pathogenicity prediction tools, and have no effect on pre-mRNA splicing. According to the ACMG/AMP criteria, all of the variants were classified as P/LP/US (Table  1 ).

Clinical features and outcome of 3 new patients with NR1H4 -related cholestasis

All 3 male patients born at full-term with normal weight to non-consanguineous parents following uneventful pregnancies. The first child in family II died of unexplained liver disorders at the age of 7 months, whereas the other families did not have positive family history. All of them presented with jaundice during the first few days after birth. Normal growth and development were observed in patient 1(P1), and failure-to-thrive occurred in patients 2 (P2) and 3 (P3). Our patients have similar clinical features resembling previously reported patients, including low-GGT cholestasis, rapidly progressive liver failure/decompensated cirrhosis, vitamin K independent coagulopathy, and markedly elevated AFP levels (Table  2 ). Initial, pre-transplantation, or pre-death laboratory testing results were shown in Table  3 . In addition, our patients had recurrent severe pneumonia, splenomegaly, and elevated urinary microalbumin. Two patients (P1 and P3) had hepatomegaly and hydrocele.

The patient P1 suffered massive ascites from decompensated cirrhosis prior to liver transplantation (LT). He had a positive plasma Epstein-Barr virus DNA from 2 months post-LT until the last visit. He also underwent a single surgery due to small bowel obstruction and right-sided diaphragmatic hernia one year after LT. The patient P3 presented with hyperammonemia due to acute liver failure (ALF) and his magnetic resonance of the brain showed minor abnormalities such as widened extracerebral space and cavum septum pellucidum.

Only one patient (P1) was treated by LT at the age of 4 months, and the other two patients died of infection at 3 months of age. Up to the latest assessment, P1 had normal liver function at one-year post-transplant.

Clinical and genetic characterization of 13 NR1H4 -related PFIC patients

A total of 13 patients from 10 unrelated families were collected, with 3 new and 10 reported patients (Supplementary Table 1 ) [ 4 , 8 , 9 , 10 ]. Eight were males, 4 were females, and one patient’s gender was unknown. All patients were delivered at full term without maternal or fetal complications. The age of onset ranged from the neonatal period to 17 months, with the median age of onset being 7 days after birth. Twelve out of 13 patients showed neonatal jaundice in the early neonatal period (7 patients, 0–6 days) and late neonatal period (5 patients, 7–28 days), respectively. Only one patient was admitted to hospital due to jaundice and abdominal distention at the age of 17 months. Reported clinical manifestations include: cholestasis (13/13, 100%), persistently elevated AFP (11/11, 100%), coagulopathy (11/11, 100%), hypoglycemia (9/13, 69%), splenomegaly (7/13, 54%), hyperammonemia (7/13, 54%), failure to thrive (8/13, 62%), and hepatomegaly (6/13, 46%). Six of 13 patients received LT at a median age of 6.2 months (range 2–20). Only one patient died of acute infection at one year after LT. Five out of 6 patients with LT are still alive, with a median age of 6 years (range 1.3–10). Other 7 patients without LT died at a median age of 5 months (range 1.2-8). The causes of death included ALF, multiple organ dysfunction syndrome (MODS), sepsis, and others (Supplementary Table 1 ).

Eight patients had homozygous genotype and 5 patients had compound heterozygous genotype. In total, 13 different variants were detected, including 4 nonsense variants, 4 missense variants, 2 frameshift variants, one splice site variant, one in-frame insertion variant, and one large DNA fragment deletion variant. Overall, there were five variants (41.6%) in exon 5, two variants (16.7%) in exon 4, one variant (8.3%) in exon 6, one variant (8.3%) in exon 8, one variant (8.3%) in exon 9, one variant (8.3%) in intron 9 and one variant (8.3%) in exon 11 (Figure  1 ).

Schematic presentation of the farnesoid X receptor (FXR) protein and locations of 12 unique single or multiple nucleotides variants identified in our cohort and literature. The exon 5 was depicted in red, and other exons of the NR1H4 gene are depicted in blue; FXR protein domains are shown in green

Liver pathological characteristics in NR1H4 -related PFIC patients

Liver pathology was documented in 7 of 13 NR1H4 -related PFIC [ 8 , 9 ]. Characteristic pathological features included cholestasis, steatosis, micro-nodular cirrhosis, hepatocellular ballooning, fibrous tissue proliferation, fibrosis, inflammatory cell infiltration, and proliferation of bile ducts. Immunohistochemical stainings of both bile salt export pump (BESP) and FXR proteins were absent, and the multi-drug resistance protein 3 (MDR3) expression was decreased or normal in all 7 patients.

It was first discovered 7 years ago that the NR1H4 was responsible for PFIC [ 4 ]. Previous studies showed that the NR1H4 -associated PFIC had early-onset and rapid disease progression with high mortality [ 4 , 8 ]. As only few patients have been reported, current understanding of PFIC5 caused by NR1H4 defect is limited. Therefore, we performed a retrospective analysis to obtain a better understanding of clinical phenotype and outcomes of PFIC5 caused by NR1H4 in our center and literature.

The FXR, encoded by NR1H4 gene, as the master regulator of BA homeostasis, regulates BA homeostasis, biliary BA secretion, and intestinal re-absorption [ 13 , 14 , 15 ]. Compared with other PFIC patients, the PFIC5 patients caused by NR1H4 defect had significantly worse prognosis due to more rapid progression [ 8 , 16 , 17 ]. All patients without LT died and survival with native liver has not been observed. Three new patients in our cohort exhibited similar clinical characteristics as published case [ 7 , 8 ]. The liver phenotypes of all reported patients were extremely similar and presented as low GGT neonatal cholestasis with rapid progression to ALF (with/without related complications such as hypoglycemia, hyperammonemia, coagulopathy, hepatosplenomegaly, hydrothorax, and ascites) [ 8 , 9 ].

While NR1H4 gene is predominantly expressed in liver and intestine, it also presents in kidney, spleen, heart, gallbladder, pancreas, adrenal glands, bone marrow, and other tissues [ 18 , 19 , 20 , 21 ]. We further summarized the extra-hepatic phenotypes of 13 patients. Of those, the failure to thrive was the most common finding. Other extrahepatic manifestations were also described, such as atrial septal defect, butterfly vertebra, decreased bone mineral density, intestinal obstruction, diaphragmatic hernia, inguinal hernia, and iris coloboma. Although NR1H4 is highly expressed in the intestine, recurrent or severe diarrhea has not been observed in patients with NR1H4 -related disorder [ 8 , 9 , 10 ].

Notably, pharmacological therapy is typically not effective for NR1H4 disease [ 8 ]. Those patients without LT died in early infancy, and the common causes of death included ALF, MODS, and severe infection [ 8 ]. Therefore, LT may be the only curative option. Fortunately, 5 out of 6 patients are still alive after LT without serious postoperative complications, and with good clinical outcome during the follow-up. Only one patient died of acute infections one month after the transplant [ 9 ], this suggests that minimizing the risk of infection is the key to reduce morbidity and mortality associated with LT for PFIC5 patients [ 22 , 23 ].

All enrolled patients had poor prognosis with native liver. So, we were not able to analyze the relationship between genotypes and phenotype. However, we observed that 41.6% of all reported variants are located on the exon 5 of NR1H4 gene. Exon5 encodes a highly conserved DNA binding domain of FXR by binding to specific DNA sequences called hormone response elements, thereby possibly regulating other gene expression [ 24 , 25 ]. More cases and further studies are needed to confirm whether exon 5 is a susceptible or hotspot region for NR1H4 gene mutation.

NR1H4 -related PFIC is characterized by severe neonatal cholestasis, rapid progression to liver failure, and early death. LT might be the only lifesaving therapy that can lead to cure. At present, no severe complications of LT related to NR1H4 gene were observed, but long-term outcome of LT still needs to be validated in more patients.

Data availability

All data generated or analyzed during this study are included in this published article and its supplementary information files.

Abbreviations

Association for Molecular Pathology

American College of Medical Genetics

Acute liver failure

High alpha-fetoprotein

Bile salt export pump

Farnesoid X receptor

Glutamyl transferase

Likely pathogenic

• Liver transplantation

Multi-drug resistance protein 3

Nonsense-mediated mRNA decay

Progressive familial intrahepatic cholestasis

Uncertain significant

Sticova E, Jirsa M, Pawlowska J. New insights in genetic cholestasis: from molecular mechanisms to clinical implications. Can J Gastroenterol Hepatol. 2018; 2018:2313675.

Amirneni S, Haep N, Gad MA, Soto-Gutierrez A, Squires JE, Florentino RM. Molecular overview of progressive familial intrahepatic cholestasis. World J Gastroenterol. 2020;26:7470–84.

Article   CAS   PubMed   PubMed Central   Google Scholar  

Vitale G, Gitto S, Vukotic R, Raimondi F, Andreone P. Familial intrahepatic cholestasis: new and wide perspectives. Dig Liver Dis. 2019;51:922–33.

Article   CAS   PubMed   Google Scholar  

Gomez-Ospina N, Potter CJ, Xiao R, Manickam K, Kim MS, Kim KH, et al. Mutations in the nuclear bile acid receptor fxr cause progressive familial intrahepatic cholestasis. Nat Commun. 2016;7:10713.

Sambrotta M, Strautnieks S, Papouli E, Rushton P, Clark BE, Parry DA, et al. Mutations in tjp2 cause progressive cholestatic liver disease. Nat Genet. 2014;46:326–8.

Qiu YL, Gong JY, Feng JY, Wang RX, Han J, Liu T, et al. Defects in myosin vb are associated with a spectrum of previously undiagnosed low gamma-glutamyltransferase cholestasis. Hepatology. 2017;65:1655–69.

Cariello M, Piccinin E, Garcia-Irigoyen O, Sabba C, Moschetta A. Nuclear receptor fxr, bile acids and liver damage: introducing the progressive familial intrahepatic cholestasis with fxr mutations. Biochim Biophys Acta Mol Basis Dis. 2018;1864:1308–18.

Himes RW, Mojarrad M, Eslahi A, Finegold MJ, Maroofian R, Moore DD. Nr1h4-related progressive familial intrahepatic cholestasis 5: further evidence for rapidly progressive liver failure. J Pediatr Gastroenterol Nutr. 2020;70:e111–3.

Czubkowski P, Thompson RJ, Jankowska I, Knisely AS, Finegold M, Parsons P, et al. Progressive familial intrahepatic cholestasis - farnesoid x receptor deficiency due to nr1h4 mutation: a case report. World J Clin Cases. 2021;9:3631–6.

Article   PubMed   PubMed Central   Google Scholar  

Chen HL, Li HY, Wu JF, Wu SH, Chen HL, Yang YH, et al. Panel-based next-generation sequencing for the diagnosis of cholestatic genetic liver diseases: clinical utility and challenges. J Pediatr. 2019;205:153–9.

Article   PubMed   Google Scholar  

Yang L, Kong Y, Dong X, Hu L, Lin Y, Chen X, et al. Clinical and genetic spectrum of a large cohort of children with epilepsy in China. Genet Med. 2019;21:564–71.

Richards S, Aziz N, Bale S, Bick D, Das S, Gastier-Foster J, et al. Standards and guidelines for the interpretation of sequence variants: a joint consensus recommendation of the American college of medical genetics and genomics and the association for molecular pathology. Genet Med. 2015;17:405–24.

Chiang J, Ferrell JM. Discovery of farnesoid x receptor and its role in bile acid metabolism. Mol Cell Endocrinol. 2022;548:111618.

Rausch M, Samodelov SL, Visentin M, Kullak-Ublick GA. The farnesoid x receptor as a master regulator of hepatotoxicity. Int J Mol Sci 2022;23.

Keitel V, Droge C, Haussinger D. Targeting fxr in cholestasis. Handb Exp Pharmacol. 2019;256:299–324.

Hassan S, Hertel P. Overview of progressive familial intrahepatic cholestasis. Clin Liver Dis. 2022;26:371–90.

Pfister ED, Droge C, Liebe R, Stalke A, Buhl N, Ballauff A, et al. Extrahepatic manifestations of progressive familial intrahepatic cholestasis syndromes: presentation of a case series and literature review. Liver Int. 2022;42:1084–96.

Yan N, Yan T, Xia Y, Hao H, Wang G, Gonzalez FJ. The pathophysiological function of non-gastrointestinal farnesoid x receptor. Pharmacol Ther. 2021;226:107867.

Fu T, Li Y, Oh TG, Cayabyab F, He N, Tang Q, et al. Fxr mediates ilc-intrinsic responses to intestinal inflammation. Proc Natl Acad Sci U S A. 2022;119:e2081926177.

Article   Google Scholar  

Xu S, Jia P, Fang Y, Jin J, Sun Z, Zhou W, et al. Nuclear farnesoid x receptor attenuates acute kidney injury through fatty acid oxidation. Kidney Int. 2022;101:987–1002.

Zheng Y, Sun W, Wang Z, Liu J, Shan C, He C et al. Activation of pancreatic acinar fxr protects against pancreatitis via osgin1-mediated restoration of efficient autophagy. Research (Wash D C). 2022; 2022:9784081.

Smith SK, Miloh T. Pediatric liver transplantation. Clin Liver Dis. 2022;26:521–35.

Selimoglu MA, Kaya S, Gungor S, Varol FI, Gozukara-Bag HG, Yilmaz S. Infection risk after paediatric liver transplantation. Turk J Pediatr. 2020;62:46–52.

Jiang L, Zhang H, Xiao D, Wei H, Chen Y. Farnesoid x receptor (fxr): structures and ligands. Comput Struct Biotechnol J. 2021;19:2148–59.

Laffitte BA, Kast HR, Nguyen CM, Zavacki AM, Moore DD, Edwards PA. Identification of the dna binding specificity and potential target genes for the farnesoid x-activated receptor. J Biol Chem. 2000;275:10638–47.

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Acknowledgements

The authors thank the patients’ families for their participation.

This study was supported by grants from Key Development Program of Children’s Hospital of Fudan University (EK2022ZX05).

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XXB designed and supervised the study, and involved in the draft and revision of the manuscript; LZD collected data and analyzed relevant information; LZD wrote the manuscript; LYC and ZJ provided clinical information for the work; WJS clinically managed patients. All authors approved the final manuscript.

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Correspondence to Xin-Bao Xie .

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Li, ZD., Li, YC., Jing-Zhao et al. NR1H4 disease: rapidly progressing neonatal intrahepatic cholestasis and early death. Orphanet J Rare Dis 19 , 171 (2024). https://doi.org/10.1186/s13023-024-03166-1

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Received : 07 November 2023

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DOI : https://doi.org/10.1186/s13023-024-03166-1

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Orphanet Journal of Rare Diseases

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• Published: 11 November 2023

Towards functionally individualised designed footwear recommendation for overuse injury prevention: a scoping review

• Patrick Mai   ORCID: orcid.org/0000-0001-7076-651X 1 , 2 , 3 ,
• Leon Robertz 1 ,
• Johanna Robbin 2 ,
• Kevin Bill 1 ,
• Gillian Weir 4 ,
• Markus Kurz 5 ,
• Matthieu B. Trudeau 6 ,
• Karsten Hollander 7 ,
• Joseph Hamill 4 &
• Steffen Willwacher 1 , 2  

BMC Sports Science, Medicine and Rehabilitation volume  15 , Article number:  152 ( 2023 ) Cite this article

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Injury prevention is essential in running due to the risk of overuse injury development. Tailoring running shoes to individual needs may be a promising strategy to reduce this risk. Novel manufacturing processes allow the production of individualised running shoes that incorporate features that meet individual biomechanical and experiential needs. However, specific ways to individualise footwear to reduce injury risk are poorly understood. Therefore, this scoping review provides an overview of (1) footwear design features that have the potential for individualisation; and (2) the literature on the differential responses to footwear design features between selected groups of individuals. These purposes focus exclusively on reducing the risk of overuse injuries. We included studies in the English language on adults that analysed: (1) potential interaction effects between footwear design features and subgroups of runners or covariates (e.g., age, sex) for running-related biomechanical risk factors or injury incidences; (2) footwear comfort perception for a systematically modified footwear design feature. Most of the included articles ( n  = 107) analysed male runners. Female runners may be more susceptible to footwear-induced changes and overuse injury development; future research should target more heterogonous sampling. Several footwear design features (e.g., midsole characteristics, upper, outsole profile) show potential for individualisation. However, the literature addressing individualised footwear solutions and the potential to reduce biomechanical risk factors is limited. Future studies should leverage more extensive data collections considering relevant covariates and subgroups while systematically modifying isolated footwear design features to inform footwear individualisation.

Individualised footwear bears the potential to alter biomechanics and, subsequently, the individual injury risk profile. Since different footwear modifications modulate risk factors for specific overuse injuries diffently, individualised footwear solutions must be designed for specific overuse injuries by targeting injury-specific biomechanical risk factors. The influence of various footwear modifications on biomechanical risk factors concerning environmental constraints, athlete anthropometry, and experience level has been documented only to a limited extent and requires further research. In addition to minimising biomechanical risk factors, the comfort and fit of the shoe should be considered to design an individually optimal shoe.

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Introduction

Running is one of the most popular global sports activities, likely because of its positive impact on physical and mental health and the simplicity of the equipment needed [ 1 , 2 , 3 ]. According to a 2020 data report from Strava, a social network for athletes, more than 3 billion kilometers were covered by this running community in 2020 alone [ 4 ]. However, with injury prevalences up to 79%, running is also associated with a high incidence of running-related overuse injuries (RRI) [ 5 ]. The onset of RRI is multifactorial. Risk factors are typically framed as intrinsic (e.g., genes, sex, age) and extrinsic (e.g., biomechanical, training-related, environmental) [ 6 ]. Other frameworks center around the causal biological mechanism to understand the multifactorial etiology of RRI [ 7 ]. Mechanically, the onset of RRI is a result of continuously exceeding the structure-specific stress capacity without sufficient resting periods for tissue remodeling (Fig.  1 ). Directly determining the individual structure-specific stress characteristics (e.g., amplitude, duration, frequency, distribution) and the underlying neuromuscular control strategies remain challenging [ 8 , 9 ]. In the complex puzzle of RRI, biomechanical risk factors (BRFs) are surrogate variables that link running biomechanics and injury risk [ 10 ]. Mechanically, footwear is believed to reduce BRFs by altering the distribution of structure-specific stress applied per stride (short term), reducing the cumulative stress within and across multiple running sessions. As a result, running footwear can affect the positive adaptation of biological tissue (long term), allowing the tissue greater capacity to tolerate more stress [ 6 ].

Interaction of risk factors that influence the workload of biological tissues. Schematic overview of an individual injury risk profile. Accumulated risk for a specific overuse injury is the sum of non-modifiable and modifiable risk factors

Since the introduction of the first commercial running shoe in the early twentieth century, the footwear industry has seen significant evolution, notably by the 1970s development of cushioned midsoles aiming to attenuate the vertical impact force [ 11 , 12 ]. However, thicker, more cushioned midsoles resulted in an inherently less stable base of support [ 11 ]. In the early 1990s, footwear manufacturers introduced motion control technologies to support biomechanical foot stability, a concept still largely governed today by foot guidance and shock attenuation principles. [ 11 , 12 , 13 ]. While running shoes are commercially available in a multitude of different designs and functions nowadays, limited research focuses on the specificity of footwear relative to an individual's anatomy and biomechanics and injury rates remain high [ 14 ]. Currently, there is limited evidence that running footwear with stability and cushioning elements could reduce RRI rates [ 15 ]. However, drastic footwear modifications such as oversimplified designs (e.g., minimal shoes) or over-designed modifications, combined with insufficient habituation time, can result in the onset of RRI [ 16 , 17 , 18 ]. New approaches, e.g., the comfort filter, habitual motion path theory, and the preferred movement path theory, linking RRIs to uncomfortable perceived shoes, are becoming increasingly established in the running community and may serve as an opportunity to reduce injuries in the future [ 12 , 19 , 20 ]. These new concepts aim to enhance the subject-specific response to footwear.

Understanding the individual response to footwear is critical since the number of footwear design features (FDF) has increased substantially (Fig.  2 ). The individualisation of footwear is further motivated by the observation that today's running community is as diverse as ever in human history [ 12 ]. Runners differ in their experience levels, running behaviours, strength capacities, and anthropometrics. In the past, the individualisation of footwear was time- and cost-intensive and, thus, mostly limited to elite athletes. Today, rapid additive manufacturing processes (e.g., 3D printing) enable individualised midsoles and fabrics for a broader audience [ 21 , 22 ]. These manufacturing technologies might further allow footwear functions to match runners' individual needs, thus potentially reducing the risk of RRI. However, it is unclear which FDF bear the highest potential for individualisation. Further, it is not well understood which characteristics (e.g., age, sex, training environment) of runners determine the details of the individualisation process. Although shoe orthopedists have supplied runners with customised footwear for decades, the modifications of these features are mainly based on experience due to the limited scientific evidence available. Therefore, the purpose of this scoping review was to provide: (1) an overview of footwear design features that might have a potential for individualisation; and (2) a systematic overview of the literature on the differential response to footwear design features between selected groups of individuals. In particular, the potential of running shoe individualisation to reduce the magnitudes of injury-specific BRFs will be evaluated.

An assembly drawing of the various construction elements of common running footwear with their functional roles (left-hand side). Categorisation of different footwear design features with the fulfilled function (right-hand side). Letters in brackets link the functional role of footwear to its modifiable footwear design feature(s) (e.g., breathability can be changed by manipulating the textile fabric)

The review team drafted and revised the scoping review protocol [ 23 ] using the PRISMA checklist ( Supplementary Information (SI 1 ). For the scoping review, we included studies in the English language on adults that analysed: (1) the interaction effects between footwear design features and subgroups of runners or covariates (e.g., age, sex) on BRFs; (2) BRFs without considering covariates; (3) injury incidences and (4) footwear perception for a systematically modified footwear design feature. Although studies that ignore covariates do not immediately inform different subgroups of runners about a running shoe lowering injury risk, they may assist in identifying a systematic shoe response and thus help design FDF graduations. We selected the BRFs for the most common overuse injuries (Table 1 ) from a recently published systematic review [ 10 ]. The most common overuse injuries in distance running include Achilles tendinopathy (AT), tibial stress fractures (TSF), plantar fasciitis (PF), iliotibial band syndrome (ITBS), patella femoral pain syndrome (PFPS), medial tibial stress syndrome (MTSS) [ 5 ]. A systematic literature search was performed on the PubMed database (Fig.  3 between June 2021 and April 2022). We used FDF-specific search strings (see SI2 for details). Each search string contained items to identify articles that analysed the effect of footwear while running (runn* OR jogg*). The second item of the search string described a specific FDF or the function of a feature (e.g., midsole AND hardness OR cushion*). To address publications on footwear research only, we applied an additional combination of search string items (footwear OR shoe OR shod). Five authors screened titles and abstracts to reject irrelevant articles. Subsequently, two authors read each relevant article's full text and discussed it to assess their eligibility. During the full-text screening, relevant articles were additionally sourced through the reference lists and a co-citation method using the bibliographic coupling concept ( www.connectedpapers.com ). Further, data on study characteristics were extracted including publication details (author and year), population details (sample size), data collection methods, running speeds, covariates considered (if applicable), and biomechanical outcome variables, as well as a detailed description of the footwear studied.

The flow chart of the search and screening procedure

Running shoes are often characterised based on their cushioning and motion control functionality. Consequently, we have categorised the literature review results into these sections. We discuss additional FDF that did not fit into the first two sections in a subsequent part, followed by an upper construction segment. In each chapter, we introduce a brief description of the FDF. Next, we present the results of studies, taking covariates into account and analysing BRFs. We further discuss studies that investigated BRFs without considering covariates. Finally, we place our findings in the context of the FDF's potential to minimise the development of running-related overuse injuries (RRI). We identified 107 articles that met our inclusion criteria (Fig.  4 , Supplementary 3 Table 1-12). Most of these articles were published at the start of the twenty-first century and primarily featured data from male runners (Fig.  5 ). We acknowledge a data gap in running footwear research, which aligns with the female data gap in sport and exercise science [ 24 ].

A Scatter plot of the included articles. Articles for each footwear design feature are separated by the number of articles considering covariates (y-axis) and running-related biomechanical risk factors (x-axis). If applicable, covariates for each footwear design feature are reported. According to a recent Delphi study, scatters are scaled to their importance [ 25 ]. Larger diameters represent a higher level of importance, and smaller diameters a lower level of importance. White scatters were not reported in the Delphi study and are not scaled

The publication timeline of the included articles, separated by the different footwear design features. Each pie chart represents one study with the fraction of male (dark-grey) and female (light-grey) runners. Pie charts are scaled to the number of runners included in the study. Larger diameters indicate larger sample sizes, and smaller diameters indicate smaller sample sizes

Cushioning systems

Cushioned midsoles were one of the first FDF introduced to modern running shoes. They were developed to provide a protective layer, attenuate the shock caused by the collision of the foot with the ground, and reduce local plantar pressure peaks [ 26 ]. The cushioning characteristics are modified in the midsole through material and geometry changes.

Midsole compression stiffness and hardness

Midsole compression stiffness, also known as hardness, is a fundamental material property that measures the deformation caused by an area load. In the past, midsoles were constructed with uniformly distributed compression stiffness. However, they can now be tailored to individually cushioned midsoles with varying properties at different locations due to the viscoelastic properties of the material [ 27 ].

Twelve of thirty-five articles identified through our literature search considered covariates when analysing the response to differently cushioned midsoles (Fig.  4 , Supplementary Table 1 ). Malisoux et al. considered the runner's body mass as a covariate [ 28 ]. Athletes reported fewer injuries when running in softer midsoles, and lighter runners in hard shoes showed a greater risk of developing an RRI than heavier runners. Three articles investigated the biomechanical response of midsoles with varying hardness during different running speeds. Nigg et al. found that the vertical GRF loading rate increases with speed independent of the cushioning variations, while another study showed unchanged GRF loading rates with footwear of varying cushioning at different speeds, and yet another study showed lower GRF loading rates in harder midsoles with no dependence on running speed [ 29 , 30 , 31 ]. Running distance or running duration has been considered by five studies [ 32 , 33 , 34 , 35 , 36 ]. None of the studies found significant footwear-by-time/distance interaction effects on vertical GRF loading rates, ground contact times, peak rearfoot eversion angles, and knee flexion angle at initial contact. One article considered the runner's foot strike pattern as a covariate [ 37 ]. Rearfoot strikers reduced the vertical GRF loading rate in a neutrally cushioned shoe, and mid- and forefoot strikers reduced the vertical GRF loading rate in a minimal shoe [ 37 ]. We identified one study considering the stiffness of the running surface as a covariate [ 38 ]. However, no main and interaction effects were observed in ground contact time and knee flexion angle at touchdown. Another study analysed the effect of surface inclination and midsole cushioning [ 39 ]. The authors showed that vertical GRF loading rates are equal when running on different surfaces with either a neutral or a cushioned running shoe. Although studies have examined a variety of covariates, there is much conjecture in the literature regarding their influence on biomechanical measures related to RRI, and no conclusive evidence to suggest that any one covariate is more important than another.

When considering the effects of midsole hardness on BRFs without considering covariates, five studies found reduced peak rearfoot eversion in harder midsoles than in softer midsoles [ 40 , 41 , 42 , 43 , 44 ]. However, four studies found unchanged peak rearfoot eversion angles when running in soft and hard midsoles [ 34 , 45 , 46 , 47 ]. Four studies reported that different midsole hardness could not systematically affect the rearfoot eversion range of motion [ 40 , 44 , 45 , 48 ]. In contrast, one study found a reduction in the rearfoot eversion range of motion in hard midsoles [ 47 ], and another study found that the range of motion of the rearfoot was lower when runners were running in softer midsoles [ 49 ]. Conflicting findings were also observed for the rearfoot inversion angle at initial ground contact. One study found a reduction in rearfoot inversion when running in soft midsoles [ 40 ], and others found reduced inversion angles when running in hard midsoles [ 40 , 48 ]. Conflicting findings have also been reported for the vertical GRF loading rate. Some studies found an increased vertical GRF loading rate in more cushioned than less cushioned shoes [ 29 , 34 ]. Other studies found no effects of cushioning [ 46 , 50 , 51 , 52 ], while others found decreased vertical GRF loading rate in cushioned shoes [ 41 ]. Only a few studies were identified addressing the effects of different cushioning characteristics on BRFs at more proximal joints. One article's qualitative data showed that the knee abduction angle during the stance phase was reduced when running in softer than harder midsoles [ 53 ]. In contrast, another study found lower peak knee abduction angles when the midsole was manufactured with harder material [ 47 ]. A study by Malisoux and colleagues found that both soft and hard midsoles did not change peak hip abduction angles and moments and peak hip internal rotation angles [ 45 ]. When considering ground contact time as BRF for PFPS, most studies found no effect of midsole cushioning [ 29 , 36 , 38 , 45 , 49 , 51 , 54 , 55 , 56 ]. Overall, studies analyzing BRFs without considering covariates, resulted in inconsistent and conflicting findings. Interestingly, the footwear comfort perception reported by participants tends to be higher in regions where softer material is allocated than in those with harder materials [ 42 , 49 , 57 , 58 ].

In summary, the current literature suggests that the midsole hardness can potentially reduce the overall injury risk when adjusted to the runner's body mass. Reduction in vertical GRF loading rates and subsequent minimizing PF injury risk could be achieved by individualising midsole cushioning to the runner's foot strike pattern. Specifically, rearfoot strikers might benefit from cushioned shoes, while fore- and midfoot strikers could find minimal shoes advantageous. The lower vertical GRF loading rates observed in neutral shoes compared to cushioned shoes when running downhill suggest that customised midsole cushioning tailored to a runner's training terrain could benefit runners with a PF history. Based on the limited literature, surface stiffness, running distance, and fatigue might be less important when individualising midsole hardness. Harder midsoles can reduce BRFs associated with MTSS, TSF, AT (rearfoot eversion movement), and ITBS (ground contact times). Indications that different shoe cushioning may alter vertical GRF loading rates are contradictory, and BRFs at more proximal joints have not been well studied.

Midsole geometry

Running footwear is often designed with a height gradient from the heel to the forefoot. Running shoes are defined by their heel and forefoot heights, with the difference between the two known as the heel-toe drop. Unlike neutral or motion-control shoes, minimal footwear is typically designed with a lower heel-toe drop. An increase in footwear minimalism generally shifts the foot strike pattern of rearfoot strikers towards a mid- or forefoot strike pattern, and it is further assumed to reduce impact loading parameters [ 59 , 60 ].

We identified eighteen articles investigating the effects of geometrical midsole modifications matching our inclusion criteria (Fig.  4 , Supplementary Table 2 ). Out of the eighteen articles, nine accounted for a covariate. The runner's experience was considered in one article [ 61 ]. During a six-month follow-up, it was shown that occasional runners (< 6 months running experience) had reduced injury rates, and recreational runners (≥ 6 months running experience) had increased injury rates when running in footwear with lower heel-toe drop. A subset of this data demonstrated that midsoles with different heel-toe drops were not able to reduce peak rearfoot eversion angle and ground contact time [ 62 ]. However, runners who trained for six months in footwear with higher heel-toe drops increased the peak knee abduction angle. On the contrary, runners who trained for six months in footwear with lower heel-toe drops reduced the peak knee abduction angle. Running surface as a covariate was considered by one study [ 63 ]. The researchers found smaller knee flexion angles for larger heel-toe drops when running on a treadmill. However, when running overground, the knee flexion angle was not changed when running in shoes with different heel-toe drops. The authors found that increasing the heel-toe drop led to lower vertical GRF loading rates overground, but decreasing the heel-toe drop reduced vertical GRF loading rates during treadmill running. Different running speeds as a covariate were considered by four articles [ 64 , 65 , 66 , 67 ]. One study found no changes in the knee flexion angle at initial contact when running at different speeds in midsoles with different heel-toe drop designs [ 64 ]. Another study showed that while ground contact time decreased with increasing speed, increasing the heel-toe drop resulted in increased contact time [ 65 ]. Other researchers also showed similar results when systematically altering running speed and heel-toe drop [ 66 ]. Running speed did not influence the effects of heel-toe drop modifications on vertical GRF loading rates or time spent in rearfoot eversion [ 67 ]. The interaction effects of running time and geometrical midsole modifications were investigated in two studies using the same data set [ 68 , 69 ]. However, neither of the studies reported interaction effects on included BRFs (rearfoot movement, contact time, and knee flexion angle at initial ground contact). Nevertheless, both studies reported longer ground contact times, lower rearfoot eversion range of motion, and greater knee flexion angles at initial contact in thicker than thinner midsoles.

Concerning the general effects of midsole geometries on BRFs without considering covariates, most of the included studies have addressed the effect of midsole geometry on GRF parameters. An increase in heel-toe drop has been reported to reduce vertical GRF loading rates [ 70 , 71 , 72 , 73 ]. Diverse results have been reported for midsole thickness, for which one study found lower vertical GRF loading rates in thicker than thinner midsoles [ 74 ], whereas another study could not identify any differences [ 75 ]. Three studies showed that geometrical changes at the midsole do not affect rearfoot inversion at touchdown [ 68 , 69 , 70 ]. Three articles showed that the knee flexion angle at touchdown remains unchanged independent of geometrical midsole configurations [ 72 , 75 , 76 ]. Only one study collected comfort perception data from fifteen male runners [ 77 ]. However, no difference in comfort was observed when the heel-toe drop was systematically altered.

Summarising the results, individualisation of heel-toe drop based on runner experience may reduce the risk of RRI. Although the underlying biomechanical mechanism remains unknown, a gradual transition from shoes with different heel-to-toe drops may allow adequate adaptation of the biological tissues. Running surfaces can affect the response to heel-toe drop alterations by influencing vertical GRF loading rates and knee flexion angles. Runners with a history of PF training on treadmills may benefit from shoes with a lower heel-toe drop, while those with a history of ITBS may benefit from a higher drop. During fatigue, geometric midsole modifications may not affect rearfoot eversion movement or ground contact times. Thinner midsoles with a lower heel-toe drop may reduce ground contact times, peak rearfoot eversion angle and rearfoot eversion duration. Hence, these modifications might be recommended for runners with a risk or a history of PFPS, TSF, or MTSS. Moreover, thicker midsoles with a higher heel-toe drop might shift BRFs related to AT and PF (rearfoot eversion range of motion and vertical GRF loading rate) to potentially less critical BRF magnitudes.

Motion control features

Motion control, also called stability, in footwear refers to how the shoe limits pronation (calcaneal eversion) or supination (calcaneal inversion) during the support phase. Much research has been devoted to FDF that purports to control pronation or eversion motion, motivated by the retrospective observations that increased pronation angle is associated with RRI [ 10 , 78 , 79 , 80 ]. Over the initial period of footwear research, various midsole technologies were designed to increase rearfoot stability, including altering the midsole hardness, location of material inserts, flares, arch support systems, and postings. One of the few identified studies utilized a randomized controlled trial with a six-month follow-up. The findings revealed that recreational runners with a motion control shoe developed fewer RRI than runners receiving a standard running shoe [ 15 ]. Interestingly, motion-control shoes' effectiveness in reducing RRI development was more pronounced for runners with pronated feet, indicating some potential for footwear individualisation.

Postings in athletic footwear incorporate elements with higher material densities in the medial rearfoot region and have been reported to limit rearfoot eversion [ 81 ]. Unlike wedges, postings are designed without gradual height differences [ 82 ].

Three of seven articles identified through our literature search considered covariates in their analysis (Fig.  4 , Supplementary Table 3 ). The runner's age was considered by one article [ 83 ]. Medial posts effectively reduced the amount of rearfoot eversion in older compared to younger female runners, while vertical GRF loading rates, peak knee abduction moments, and peak knee internal rotation angles remained unchanged. When considering the runners' fatigue as a covariate, two articles found that rearfoot eversion movement (peak and range of motion) was lower when running in a medially posted than in a neutral running shoe when the runner's fatigue increased [ 84 , 85 ].

When not considering covariates or subgroups of runners, medial postings can reduce peak rearfoot eversion angles and eversion range of motion [ 86 , 87 ]. Peak knee internal rotation angles are reported to be reduced when running in footwear with medial postings [ 83 , 88 ]. However, footwear with postings might increase peak hip abduction moments [ 89 ]. Diverse results were found for vertical GRF loading rates. One study found lower vertical GRF loading rates in midsoles without medial posts [ 87 ], and another found unchanged vertical GRF loading rates in shoes with and without postings [ 83 ]. Some runners have perceived the harder posting material without transitions as uncomfortable, potentially resulting in unwanted changes in their biomechanics [ 88 ].

In summary, older female runners with a history of TSF and MTSS might reduce rearfoot eversion in shoes with postings. However, medial posts do not seem to affect the risk of developing PF independent of the runners' age since changes in vertical GRF loading rates were not observable. Based on the limited literature, posted midsoles may help minimise BRFs (rearfoot eversion movement) associated with AT, MTSS, or TSF as the runners’ fatigue state increases. The limited literature suggests that individualised postings can help runners with a history of AT, MTSS, TSF, or ITBS to reduce biomechanical risk factors. Since postings might increase vertical GRF loading rates, caution needs to be taken by runners with a history of PF.

Wedges are sloped orthotic inserts, typically with mediolateral elevation, designed to increase foot stability. Mediolateral elevation under different loading conditions can be achieved by incorporating materials with different mechanical properties at distinguished locations of the wedge [ 90 ].

Three out of the ten articles identified in the literature search included a covariate in their analysis (Fig.  4 , Supplementary Table 4 ). One study considered running duration (0–30 min) as a covariate [ 91 ]. Independent of the running duration, medially wedged insoles produced lower knee abduction angular impulses than laterally wedged insoles. Another study considered different standing calcaneal angles and injury history as covariates [ 92 ]. However, wearing differently wedged insoles showed no effect on female runners' 3D knee and hip kinematics. Anterior knee pain as a covariate and the response to differently wedged insoles were considered by one article [ 93 ]. Independent of knee pain, running in medially wedged insoles reduced maximal rearfoot eversion and range of motion compared to running in footwear without wedges. None of the studies personalised the wedges to the runner's individual foot anatomy; instead, they used pre-fabricated wedges, which may have confounded these results.

Seven articles were identified investigating the effect of wedged insoles on BRFs without considering covariates. In a study in which the wedges were customised to individual dynamic barefoot plantar pressure data, all but two subjects reduced peak rearfoot eversion angles compared to footwear without wedges [ 94 ]. This finding suggests that wedges bear high potential when individualised to foot pressure mapping. Pre-fabricated medial wedges have proven effective in decreasing maximal rearfoot eversion angles and eversion range of motion [ 94 , 95 , 96 , 97 ]. When comparing footwear with and without wedges, non-systematic changes in vertical GRF loading rates and knee abduction angular impulse have been reported [ 95 , 96 , 98 , 94 , 99 , 100 ]. When the mediolateral elevation was systematically altered, no perceived comfort and stability changes were reported [ 95 ]. Moreover, neither medially nor laterally wedged insoles were able to relieve runners of patellofemoral pain [ 99 ]. One study introduced forefoot wedges with systematic changes in elevation; however, no changes in ground contact times were reported [ 101 ].

In summary, the response to medially wedged insoles is independent for shorter running durations (< 30 min) but may help runners with a history of PFPS to minimise knee abduction angular impulses; however, the effect for longer running durations (> 30 min) remains unknown. The limited literature shows that joint alignments, injury history, and knee pain are less relevant covariates when individualising wedged insoles. Medially wedged insoles might sufficiently limit rearfoot eversion movement and support runners with a history of AT, TSF, and MTSS to reduce reinjury. To attenuate vertical GRF loading rates, runners with a history of PF might refer to other FDF modifications to reduce the overuse injury risk.

Arch support systems

Arch support systems help the foot by storing and releasing elastic energy and preventing arch collapse during high loading [ 102 ]. Foot arches can be classified as flat/low, normal, or high [ 103 ]. Within the three groups, low-arched runners may exhibit greater eversion movement and velocity than high-arched runners [ 104 ]. Arch support systems can be integrated into the midsole or achieved through custom-made insoles shaped into the foot arch [ 105 ].

Our review found seven articles, four of which examined the effect of arch support systems on running biomechanics with a covariate (Fig.  4 , Supplementary Table 5 ). Two studies used foot arch height as the covariate, and they found that high-arched runners reduced vertical GRF loading rates in a shoe without arch support, while low-arched runners reduced loading rates in a shoe with arch support. However, both foot arch types experienced reduced rearfoot eversion in a motion control shoe [ 106 ]. With a subset of this data, no changes in rearfoot eversion movements for runners with different foot arch types were observed when running in shoes with and without arch support systems during a prolonged run [ 107 ]. One article accounted for the runner's foot strike pattern and found that rearfoot strikers decreased ground contact time in footwear without arch support [ 108 ]. In contrast, forefoot strikers reduced contact time in a shoe with arch support [ 108 ]. The same study found that forefoot strikers in minimal footwear reduced vertical GRF loading rates, but rearfoot strikers did not. Furthermore, training for three months in footwear with a custom-made arch support system reduced rearfoot eversion [ 105 ].

We identified three articles investigating the effect of arch support systems on BRFs without considering covariates. A study involving female runners found no effect of arch support on vertical GRF loading rates, peak rearfoot eversion angles, and peak femur rotation angles [ 46 ]. Another study also found unchanged rearfoot eversion movements (peak eversion angle and rearfoot inversion at initial ground contact) and knee abduction angles when runners with AT symptoms ran in footwear with and without arch support [ 109 ]. Although BRFs were unchanged, a 92% relief of AT symptoms was reported when wearing an insole with custom-made arch support. Finally, one study found unchanged ground contact times when running in midsoles with 20 mm and 24 mm high arch support elevations [ 101 ].

The limited literature suggests that arch support systems can potentially reduce BRFs for runners with different arch heights and a history of PF. Runner's foot strike pattern might be considered when individualising arch support systems. When individualising arch support systems to minimise BRFs associated with PFPS (ground contact time) and PF (vertical GRF loading rate), forefoot strikers might benefit from less arch support than rearfoot strikers. Moreover, customised arch support systems enhance comfort perception without changes in peak knee abduction angles and vertical GRF loading rates. Arch support might reduce rearfoot eversion movements and thus have the potential for individualisation for runners with a history of AT, TSF, and MTSS. BRFs related to ITBS (peak femur rotation angle and peak knee abduction angles) seem to change marginally and unsystematically with arch support.

Heel flares

Flares can be described as a projection of the midsole and outsole extending beyond the upper [ 25 ]. Flares can be placed medially or laterally along the outline of the midsole and were introduced to alter the rearfoot eversion angle, thus increasing foot stability by changing the ankle joint moment arm [ 110 , 111 , 112 ].

After examining all articles, we identified five matching our inclusion criteria (Fig.  4 , Supplementary Table 6 ). None of these articles investigated the effect of a covariate.

Concerning BRFs, one study altered the medial heel flare from 0° to 15°, and 30°. The 2D video-based analysis indicated higher rearfoot eversion movement in footwear without heel flares [ 81 ]. In the same study, runners running in shoes with the most extreme medial heel flare modification had, on average, lower rearfoot eversion range of motion than in shoes with less or without heel flares. These findings were supported by other research showing that footwear with heel flares can reduce the magnitude of rearfoot eversion across the entire stance phase but does not seem to reduce vertical GRF loading rates [ 110 , 112 , 113 ]. On the contrary, one study with only five runners did not show that rearfoot eversion movement (at initial ground contact, peak, and range of motion) changes when running in footwear with different heel flares [ 111 ]. From a perception perspective, heel flares can improve perceived foot stability [ 112 ].

None of the articles considered covariates (e.g., foot strike pattern), highlighting future research potential. Although we found diverse results regarding rearfoot eversion movement, midsoles with heel flares might reduce BRFs linked to AT, TSF, or MTSS. Based on the very limited body of literature, midsoles with heel flares are insufficient for reducing vertical GRF loading rates, and individualised heel flares may not target runners with a history of PF.

Crash pads are elements incorporated into the posterior-lateral midsole using softer foams, segmented geometries, air pockets, or gel-filled patches. Crash pads in the rearfoot area aim to attenuate the GRF and reduce the GRF's lever arm to the ankle joint [ 114 ].

After assessing articles for their eligibility, we identified three articles matching our inclusion criteria (Fig.  4 , Supplementary Table 7 ). Out of the three articles, one study considered the fatigue status of female runners as a covariate. As the runners' fatigue increased, wearing footwear without crash pads increased vertical GRF loading rates compared to the non-fatigue state. However, running in footwear with crash pads maintained consistent vertical GRF loading rates, even as the runners' fatigue increased. [ 115 ]. The same study found no effect of fatigue on the peak free moment amplitude.

When not considering covariates, two studies found reduced rearfoot inversion angles at touchdown in footwear with smaller compared to larger crash pad dimensions. However, there were no differences in peak rearfoot eversion angles during the stance phase of running and unsystematic changes in vertical GRF loading rates [ 114 , 116 ]. Crash pad modifications did not affect the peak free moment amplitude, ground contact time, and rearfoot eversion range of motion [ 114 , 115 , 116 ]. Changes in crash pad dimensions do not seem to influence the runner's comfort perception [ 114 ]. However, they may provide an essential tool for individualisation to tune midsole cushioning properties without increasing stack height which has been shown to increase rearfoot eversion [ 81 ].

Fatigue seems to be a relevant covariate when individualising crash pads to minimise vertical GRF loading rates, thus, might lower the risk of developing PF. However, runners with a history of TSF might need other individualised FDF to lower peak free moment amplitudes. Increasing crash pad height might help runners with plantar fascia complaints by lowering the vertical GRF loading rates. Runners with a history of AT, TSF, or MTSS might benefit from crash pads by reducing rearfoot eversion movement. Surprisingly, although the FDF aimed at attenuating the peak impulse, we have identified only two studies that have analysed vertical GRF loading rate as BRF.

Other footwear design features

Rockers in running shoes aim to reduce the strain on the toes, foot, and ankle by altering the midsole's curvature in the anterior–posterior direction, positioning the apex near the metatarsal heads, and enhancing the midstance-to-push-off transition for a smoother heel-to-toe rolling motion [ 117 ].

Each of the three identified articles considered a covariate in their analysis (Fig.  4 , Supplementary Table 8 ). One study considered running speeds as a covariate. Although running at higher speeds increases the vertical GRF loading rate, no changes in GRF loading rates were observed between shoes with and without rocker [ 118 ]. Two studies considered the foot strike pattern and found that a toe spring starting closer to the midfoot reduced pressure in the forefoot compared to a standard rocker placed at 65% of the shoe length [ 119 ]. However, runners perceived the traditional rocker as more comfortable. When compared to shoes without rockers, one study found that a rocker shoe reduced ground contact time but did not affect knee flexion angles at initial ground contact [ 120 ].

The number of studies addressing injury-specific BRFs and the effects of rocker designs is limited. Rockers involve different levels of FDF (stack height, cushioning), and therefore it is difficult to assign a specific feature to a specific BRF. More research is needed to understand if certain covariates can cause a specific change in BRFs and how different FDFs that combine a rocker design need to be tuned for individualisation.

Outsole profile

A shoe's outsole interacts with the running surface and requires attributes like traction, waterproofness, durability, and puncture resistance [ 121 ]. Material robustness might be related to running shoe comfort, and high traction might increase free moment amplitudes associated with TSF [ 122 ].

After assessing all articles for eligibility, we could not identify any articles matching our predefined inclusion criteria (Fig.  4 ). Future studies might use wearable sensors or markerless tracking systems to analyse runners wearing shoes with different outsole profiles on natural surfaces.

Flex grooves

Flex grooves and zones are included in outsoles and midsoles to enhance flexibility, facilitating metatarsophalangeal joint movement and shock absorption. Their placement is essential for the joint's variable axis and should be individualised based on foot measurements. Recent 3D measurements indicate significant variation, underscoring the need for personalized flexible zones [ 123 ].

Our literature search identified one article matching our predefined inclusion criteria (Fig.  4 , Supplementary Table 9 ). This article considered running speed as a covariate. In this study, the midsole flexibility was altered by cuts with different orientations at the heel region. Although interaction effects were only marginal when jogging or running in footwear with different groove designs, a 10% lower vertical GRF loading rate was observed in the midsole with grooves compared to the midsoles without grooves at the rearfoot [ 124 ]. Interestingly, footwear with greater flexibility is perceived as more comfortable than midsoles with less flexibility [ 125 , 126 ].

While there is limited research on the impact of flex grooves on relevant BRFs for common RRI, one identified article found that they can reduce vertical GRF loading rates, suggesting that flex grooves may be customised for runners with PF.

Longitudinal bending stiffness

The longitudinal bending stiffness can impact the running economy by optimising energy return and kinematics of the metatarsal joint and force application [ 127 , 128 , 129 , 130 , 131 ]. The bending stiffness can be modified by adding reinforcement materials or changing the geometry of stiff midsole compounds. The optimal bending stiffness depends on factors such as running speed and body weight [ 128 , 132 ].

Our literature search identified eleven articles, of which four accounted for a covariate (Fig.  4 , Supplementary Table 10 ). All four articles considered running speed as a covariate. None of these articles found a significant interaction effect on BRFs when running in footwear with different longitudinal bending stiffness at different running speeds [ 133 , 134 , 135 , 136 ]. Independent of running speed, studies reported reduced ground contact times when running in shoes with lower bending stiffness, while one article found unchanged ground contact times [ 136 ].

When not considering covariates, three studies found no changes in the GRF braking impulse when running in shoes with different bending stiffness [ 135 , 137 , 138 ]. On the contrary, a reduction in GRF braking impulse in footwear with higher bending stiffness was found in one study [ 134 ]. Eight articles found a reduction in the ground contact time [ 130 , 133 , 134 , 135 , 137 , 138 , 139 ], and two found unchanged ground contact times [ 134 , 140 ] when running in midsoles with lower bending stiffness. Although studies found lower vertical GRF loading rates [ 140 ] and increased comfort perception [ 135 ] when athletes ran in more flexible than stiffer midsoles, the relationship between BRFs and injury development when altering the longitudinal bending stiffness has not been sufficiently studied yet, but first studies have evolved showing that bones stress injuries might increase when switching to footwear with carbon fibre plates [ 18 ].

The limited body of literature suggests that fitting longitudinal bending stiffness to the runner's needs may help with treating PFPS. While reduced bending stiffness can reduce ground contact time, higher stiffness can reduce ground reaction force braking impulse. However, injury prevention and reinjury risk minimisation under the light of different longitudinal bending stiffness has been insufficiently investigated. Furthermore, flexible midsoles with lower longitudinal bending stiffness might reduce vertical GRF loading rates and potentially help runners with a history of PF.

The running shoe upper is comprised of a textile fabric and lacing system that couple the foot and shoe, with reinforcement materials used for stability and breathability. An optimal fit depends on individual foot morphology, while insufficient coupling can negate benefits from other design features. Moreover, excessive pressure can affect comfort by restricting blood supply, making individualisation important [ 141 ]. Since foot dimensions differ across sexes, ages, and ethnic origins, individualised upper bears great potential for individualisation [ 142 ].

Upper fabric

Our systematic literature search identified two articles investigating the effect of different upper modifications (Fig.  4 , Supplementary Table 11 ). None of the articles considered covariates [ 53 , 143 ].

The data indicates that a soft-sewed structured fabric reduces knee abduction angles and vertical GRF loading rates compared to a minimalist heat fusion fabric. Furthermore, the ground contact time was reduced when running in minimalist heat fusion fabric.

The current body of literature is insufficient to give recommendations for upper individualisation concerning the reduction of BRFs. Based on the limited results, upper materials might be individualised to the runner's preference.

Five articles have investigated the effect of lacing on the lower extremity joint biomechanics or subjective comfort perception (Fig.  4 , Supplementary Table 12 ).

One of five studies considered the runner's experience as a covariate. The researchers found that low-level runners perceived an irregularly (skipping eyelets) laced running shoe as more stable and comfortable than high-level runners who preferred a regular high and tight lacing pattern [ 144 ].

We identified four studies analysing BRFs without accounting for covariates. According to a study, running shoes with traditional lacing and elastic upper material were perceived as more comfortable than footwear without lacing [ 145 ]. When running in shoes with various lacings, two studies found no significant difference in the rearfoot eversion angle at initial contact [ 145 , 146 ]. The same studies found a reduction in the peak rearfoot eversion angle when running in traditionally laced shoes compared to those without traditional lacing. However, another study systematically changed lacing patterns and could not find any differences in the peak rearfoot eversion angle [ 147 ]. Different types of lacing patterns, particularly high- and tightly-laced shoes, have been shown to reduce vertical GRF loading rate at the cost of comfort [ 144 , 148 ].

Studies analysing BRFs and considering relevant covariates, e.g., foot shape, are required in the future. Notably, no studies have measured the foot-shoe coupling or the relative movement of the foot within the shoe, highlighting the potential for future research to determine individualised fits and their interactions with other FDF. Since peak rearfoot eversion angles and vertical GRF loading rates are reported to be lower when running in tightly and high-laced shoes, runners with a history of MTSS and TSF might target individualised lacing systems.

Discussion and future perspectives

Our findings suggest that studies assessing the effects of footwear on BRFs rarely take covariates into account. The literature considering covariates and BRFs is limited for heel flares, midsole longitudinal flexibility/stiffness, and upper, and rocker modifications. Especially the latter seems to have a high potential for individualised footwear solutions for rear- and forefoot strikers since remarkably different responses to non-BRFs have been reported [ 120 ].

The response of BRFs associated with MTSS, TSF, and AT to different FDF has been studied in greater detail. The recently published systematic review identified rearfoot eversion movements (peak and range of motion) as BRFs [ 10 ]. However, only considering eversion movements as BRFs might overlook the complexity of the tri-planar motion of the foot and ankle complex. Although injuries around the knee joint are the most common [ 5 ], little research has been dedicated to understanding how running footwear modifications can redistribute knee joint stress.

Currently, there are some indicators about which BRFs can be modified via certain FDF. The effect of different types of footwear on covariates such as environmental constraints, athlete anthropometry, and level of experience and their influence on BRFs has been reported (albeit limited). However, future research should investigate the effect of shoe type on other important covariates, such as training load, fatigue, running distance, and step count linked to BRFs. Advantages in markerless tracking systems and wearable sensors might leverage big data collections to analyse runners and account for relevant covariates in real-world scenarios. Moreover, the use of classical repeated-measures statistics might blur the understanding of a systematic footwear response. Although repeated-measures statistics help determine an "average" response to (two or more) footwear conditions, it does not help to understand whether these responses are systematic. Using classical mean comparisons and neglecting the individual response overlooks the complexity of footwear and shoe interaction. Reporting additional statistical metrics, e.g., individual data or rank correlations, might help other researchers understand whether a footwear response was systematic or individual.

The findings of this literature review need to be interpreted in light of some limitations. First, we included all articles that analysed BRFs or considered a covariate in their analysis. The BRFs identified by the systematic review show high uncertainty, and there are contradictory results across studies [ 149 ]. Although the causality of some BRFs remains questionable, precise measurement of BRFs is one of the few injury risk estimators footwear manufacturers, coaches, and athletes can rely on at the moment. Second, the interaction of FDF cannot be excluded (Supplementary Table 1 – 12 ). A large number of the included studies varied multiple FDF within the same experiment without controlling for the interaction effect of the modification. For example, when comparing a minimal to a neutral and motion control shoe, it is unclear which FDF have been modified and affect the biomechanical outcome. Therefore, more studies addressing FDF systematically and considering FDF interactions should be performed in the future.

There is high uncertainty on relevant covariates affecting the biomechanical response to different FDF. The aetiology behind RRI development is multifactorial, and determining a runner's risk profile is anything but trivial [ 150 ]. In running, inappropriate footwear does not per se cause an RRI. Instead, it affects the individual injury risk profile through interaction with other factors, e.g., biomechanics, training load and anthropometrics (Fig.  1 ). However, individual structure-specific stress capacities as covariates need to be considered when establishing a cause-effect relationship between footwear and injury.

In conclusion, an FDF may increase the magnitude of a BRF for one injury and decrease that of another BRF for another injury, which suggests that footwear needs to be individualised and injury-specific. However, more research is required to identify relevant covariates and consider training load characteristics. In particular, the runner's injury risk profile should be assessed in real-world scenarios to better understand the response to footwear modifications. Because little is known about important covariates, creating an individualised shoe may still require extensive laboratory-based running tests to determine BRFs and modify them with FDF. Although we reported that certain FDF bear the potential for individualisation and for reducing injury-specific BRFs, it is not recommended to individualise multiple FDF at once. Instead, FDF should be individualised gradually to avoid interactions of FDF or over-designing and simultaneously maximise footwear comfort.

Availability of data and materials

The results of the electronic search are available in the supplementary information.

Abbreviations

Achilles tendinopathy

Biomechanical risk factor(s)

Footwear design feature

Ground reaction force

Iliotibial band syndrome

Medial tibial stress syndrome

Plantar fasciitis

Patellofemoral pain syndrome

Running-related overuse injury

Tibial stress fractures

Norris R, Carroll D, Cochrane R. The effects of aerobic and anaerobic training on fitness, blood pressure, and psychological stress and well-being. J Psychosom Res. 1990;34(4):367–75.

Article   PubMed   CAS   Google Scholar  

Kruisdijk FR, Hendriksen IJM, Tak ECPM, Beekman ATF, Hopman-Rock M. Effect of running therapy on depression (EFFORT-D). Design of a randomised controlled trial in adult patients [ISRCTN 1894]. BMC Public Health. 2012;12:50.

Article   PubMed   PubMed Central   Google Scholar  

Cooney GM, Dwan K, Greig CA, Lawlor DA, Rimer J, Waugh FR, et al. Exercise for depression. Cochrane Database Syst Rev. 2013;(9). Zitiert 13. März 2021. Verfügbar unter: https://www.cochranelibrary.com/cdsr/doi/10.1002/14651858.CD004366.pub6/full .

Strava releases 2021 Year In Sport Data Report. Strava. Zitiert 13. März 2021. Verfügbar unter: https://blog.strava.com/press/yis2021/ .

van Gent RN, Siem D, van Middelkoop M, van Os AG, Bierma-Zeinstra SMA, Koes BW, et al. Incidence and determinants of lower extremity running injuries in long distance runners: a systematic review * COMMENTARY. Br J Sports Med. 2007;41(8):469–80.

Willwacher S. Running Shoes: Injury Protection and Performance Enhancement. In: Müller B, Wolf SI, Brueggemann GP, Deng Z, McIntosh A, Miller F, et al. Herausgeber. Handbook of Human Motion. Cham: Springer International Publishing; 2017 [zitiert 30. Oktober 2019]. S. 1–16. Verfügbar unter: http://link.springer.com/10.1007/978-3-319-30808-1_121-1 .

Bertelsen ML, Hulme A, Petersen J, Brund RK, Sørensen H, Finch CF, et al. A framework for the etiology of running-related injuries. Scand J Med Sci Sports. 2017;27(11):1170–80.

Hoenig T, Ackerman KE, Beck BR, Bouxsein ML, Burr DB, Hollander K, et al. Bone stress injuries. Nat Rev Dis Primers. 2022;8(1):1–20.

Article   Google Scholar  

Millar NL, Silbernagel KG, Thorborg K, Kirwan PD, Galatz LM, Abrams GD, et al. Tendinopathy. Nat Rev Dis Primers. 2021;7(1):1.

Article   PubMed   Google Scholar  

Willwacher S, Kurz M, Robbin J, Thelen M, Hamill J, Kelly L, et al. Running-Related Biomechanical Risk Factors for Overuse Injuries in Distance Runners: A Systematic Review Considering Injury Specificity and the Potentials for Future Research. Sports Med. 2022. Zitiert 17. 2022. Verfügbar unter: https://link.springer.com/10.1007/s40279-022-01666-3 .

Davis IS. The re-emergence of the minimal running shoe. J Orthop Sports Phys Ther. 2014;44(10):775–84.

Nigg BM, Baltich J, Hoerzer S, Enders H. Running shoes and running injuries: mythbusting and a proposal for two new paradigms: ‘preferred movement path’ and ‘comfort filter.’ Br J Sports Med. 2015;49(20):1290–4.

Brubaker CE, James SL. Injuries to runners. J Sports Med. 1974;2(4):189–98.

Lopes AD, HespanholJúnior LC, Yeung SS, Costa LOP. What are the main running-related musculoskeletal injuries? A Systematic Review. Sports Med. 2012;42(10):891–905.

Malisoux L, Chambon N, Delattre N, Gueguen N, Urhausen A, Theisen D. Injury risk in runners using standard or motion control shoes: a randomised controlled trial with participant and assessor blinding. Br J Sports Med. 2016;50(8):481–7.

Rixe JA, Gallo RA, Silvis ML. The Barefoot Debate: Can Minimalist Shoes Reduce Running-Related Injuries? Curr Sports Med Rep. 2012;11(3):160–5.

Ridge ST, Johnson AW, Mitchell UH, Hunter I, Robinson E, Rich BSE, et al. Foot bone marrow edema after a 10-wk transition to minimalist running shoes. Med Sci Sports Exerc. 2013;45(7):1363–8.

Tenforde A, Hoenig T, Saxena A, Hollander K. Bone Stress Injuries in Runners Using Carbon Fiber Plate Footwear. Sports Med. 2023 [zitiert 21. März 2023]; Verfügbar unter: https://doi.org/10.1007/s40279-023-01818-z .

Trudeau MB, Willwacher S, Weir G, Rohr E, Ertel C, Bruggemann GP, et al. A novel method for estimating an individual’s deviation from their habitual motion path when running. Footwear Sci. 2019;11(3):135–45.

Willwacher S, Mählich D, Trudeau MB, Hamill J, Weir G, Brüggemann GP, et al. The habitual motion path theory: Evidence from cartilage volume reductions in the knee joint after 75 minutes of running. Sci Rep. 2020;10(1):1363.

Article   PubMed   PubMed Central   CAS   Google Scholar  

Spanks JC. Article of footwear with a lattice sole structure. Google Patents. 2018.

Google Scholar  

Sabantina L, Kinzel F, Ehrmann A, Finsterbusch K. Combining 3D printed forms with textile structures - mechanical and geometrical properties of multi-material systems. IOP Conf Ser: Mater Sci Eng. 2015;87:012005.

Tricco AC, Lillie E, Zarin W, O’Brien KK, Colquhoun H, Levac D, et al. PRISMA Extension for Scoping Reviews (PRISMA-ScR): Checklist and Explanation. Ann Intern Med. 2018;169(7):467–73.

Cowley ES, Olenick AA, McNulty KL, Ross EZ. “Invisible Sportswomen”: The Sex Data Gap in Sport and Exercise Science Research. Women Sport Phys Act J. 2021;29(2):146–51.

Honert EC, Mohr M, Lam WK, Nigg S. Shoe feature recommendations for different running levels: A Delphi study. PLoS ONE. 2020;15(7):e0236047.

Shorten MR. The energetics of running and running shoes. J Biomech. 1993;26:41–51.

Tung KD, Franz JR, Kram R. A Test of the Metabolic Cost of Cushioning Hypothesis during Unshod and Shod Running. Med Sci Sports Exerc. 2014;46(2):324–9.

Malisoux L, Delattre N, Urhausen A, Theisen D. Shoe Cushioning Influences the Running Injury Risk According to Body Mass: A Randomized Controlled Trial Involving 848 Recreational Runners. Am J Sports Med. 2020;48(2):473–80.

Kulmala JP, Kosonen J, Nurminen J, Avela J. Running in highly cushioned shoes increases leg stiffness and amplifies impact loading. Sci Rep. 2018;8(1):17496.

Nigg BM, Bahlsen HA, Luethi SM, Stokes S. The influence of running velocity and midsole hardness on external impact forces in heel-toe running. J Biomech. 1987;20(10):951–9.

Malisoux L, Gette P, Delattre N, Urhausen A, Theisen D. Spatiotemporal and Ground-Reaction Force Characteristics as Risk Factors for Running-Related Injury: A Secondary Analysis of a Randomized Trial Including 800+ Recreational Runners. Am J Sports Med. 2022;50(2):537–44.

Willy RW, Davis IS. Kinematic and kinetic comparison of running in standard and minimalist shoes. 2013.

Kong PW, Candelaria NG, Smith DR. Running in new and worn shoes: a comparison of three types of cushioning footwear. Br J Sports Med. 2009;43(10):745–9.

Pollard CD, Ter Har JA, Hannigan JJ, Norcross MF. Influence of Maximal Running Shoes on Biomechanics Before and After a 5K Run. Orthop J Sports Med. 2018;6(6):232596711877572.

Cornwall MarkW, McPoil TG. Can runners perceive changes in heel cushioning as the shoe ages with increased mileage?. Int J Sports Phys Ther. 2017;12(4):616.

Sanno M, Epro G, Brüggemann GP, Willwacher S. Running into Fatigue: The Effects of Footwear on Kinematics, Kinetics, and Energetics. Med Sci Sports Exerc. 2021;53(6):1217–27.

Nordin AD, Dufek JS. Footwear and footstrike change loading patterns in running. J Sports Sci. 2020;38(16):1869–76.

Hardin EC, Van Den Bogert AJ, Hamill J. Kinematic Adaptations during Running: Effects of Footwear, Surface, and Duration. Med Sci Sports Exer. 2004;838–44.

Chan ZYS, Au IPH, Lau FOY, Ching ECK, Zhang JH, Cheung RTH. Does maximalist footwear lower impact loading during level ground and downhill running? Eur J Sport Sci. 2018;18(8):1083–9.

Kersting UG, Brüggemann GP. Midsole material-related force control during heel-toe running. Res Sports Med. 2006;14(1):1–17.

Wit BD, Clercq DD, Lenoir M. The Effect of Varying Midsole Hardness on impact Forces and Foot Motion during Foot Contact in Running. J Appl Biomech. 1995;11(4):395–406.

Sterzing T, Custoza G, Ding R, Cheung JTM. Segmented midsole hardness in the midfoot to forefoot region of running shoes alters subjective perception and biomechanics during heel-toe running revealing potential to enhance footwear. Footwear Sci. 2015;7(2):63–79.

Hamill J, Bates BT, Holt KG. Timing of lower extremity joint actions during treadmill running. Med Sci Sports Exerc. 1992;24(7):807–13.

Langley B, Cramp M, Morrison SC. The Influence of Motion Control, Neutral, and Cushioned Running Shoes on Lower Limb Kinematics. J Appl Biomech. 2019;35(3):216–22.

Malisoux L, Gette P, Backes A, Delattre N, Theisen D. Lower impact forces but greater burden for the musculoskeletal system in running shoes with greater cushioning stiffness. Eur J Sport Sci. 2022;1–11.

MacLean CL, Davis IS, Hamill J. Influence of Running Shoe Midsole Composition and Custom Foot Orthotic Intervention on Lower Extremity Dynamics during Running. J Appl Biomech. 2009;25(1):54–63.

Dixon S, Nunns M, Tenbroek T. Influence of increased shoe lateral stiffness on running biomechanics in older females. 2015.

Book   Google Scholar  

Oriwol D, Sterzing T, Milani TL. The position of medial dual density midsole elements in running shoes does not influence biomechanical variables. Footwear Science. 2011;3(2):107–16.

Sterzing T, Schweiger V, Ding R, Cheung JTM, Brauner T. Influence of rearfoot and forefoot midsole hardness on biomechanical and perception variables during heel-toe running. Footwear Sci. 2013;5(2):71–9.

Bates BT. Comment on ‘The influence of running velocity and midsole hardness on external impact forces in heel-toe running.’ J Biomech. 1989;22(8–9):963–5.

Malisoux L, Delattre N, Meyer C, Gette P, Urhausen A, Theisen D. Effect of shoe cushioning on landing impact forces and spatiotemporal parameters during running: results from a randomized trial including 800+ recreational runners. Eur J Sport Sci. 2020;11:1–25.

Miller RH, Hamill J. Computer simulation of the effects of shoe cushioning on internal and external loading during running impacts. Comput Methods Biomech Biomed Engin. 2009;12(4):481–90.

Onodera AN, GaviãoNeto WP, Roveri MI, Oliveira WR, Sacco IC. Immediate effects of EVA midsole resilience and upper shoe structure on running biomechanics: a machine learning approach. PeerJ. 2017;5:e3026.

Meardon SA, Willson JD, Kernozek TW, Duerst AH, Derrick TR. Shoe cushioning affects lower extremity joint contact forces during running. Footwear Sci. 2018;10(2):109–17.

Clarke T, Frederick E, Cooper L. Effects of Shoe Cushioning Upon Ground Reaction Forces in Running. Int J Sports Med. 1983;04(04):247–51.

Article   CAS   Google Scholar  

Holowka NB, Gillinov SM, Virot E, Lieberman DE. Effects of footwear cushioning on leg and longitudinal arch stiffness during running. J Biomech. 2022;133:110869.

Wegener C, Burns J, Penkala S, Sc GDES. Effect of Neutral-Cushioned Running Shoes on Plantar Pressure Loading and Comfort in Athletes with Cavus Feet: A Crossover Randomized Controlled Trial. Am J Sports Med. 2008;36(11):2139–46.

O’Leary K, Vorpahl KA, Heiderscheit B. Effect of Cushioned Insoles on Impact Forces During Running. J Am Podiatr Med Assoc. 2008;98(1):36–41.

Lieberman DE, Venkadesan M, Werbel WA, Daoud AI, D’Andrea S, Davis IS, et al. Foot strike patterns and collision forces in habitually barefoot versus shod runners. Nature. 2010;463(7280):531–5.

Willwacher S, Regniet L, Mira Fischer K, Oberländer KD, Brüggemanna GP. The effect of shoes, surface conditions and sex on leg geometry at touchdown in habitually shod runners. Footwear Sci. 2014;6(3):129–38.

Malisoux L, Chambon N, Urhausen A, Theisen D. Influence of the Heel-to-Toe Drop of Standard Cushioned Running Shoes on Injury Risk in Leisure-Time Runners: A Randomized Controlled Trial With 6-Month Follow-up. Am J Sports Med. 2016;44(11):2933–40.

Malisoux L, Gette P, Chambon N, Urhausen A, Theisen D. Adaptation of running pattern to the drop of standard cushioned shoes: A randomised controlled trial with a 6-month follow-up. J Sci Med Sport. 2017;20(8):734–9.

Chambon N, Delattre N, Guéguen N, Berton E, Rao G. Shoe drop has opposite influence on running pattern when running overground or on a treadmill. Eur J Appl Physiol. 2015;115(5):911–8.

Hollander K, Argubi-Wollesen A, Reer R, Zech A. Comparison of Minimalist Footwear Strategies for Simulating Barefoot Running: A Randomized Crossover Study. PLoS One. 2015;10(5). Zitiert 12. Oktober 2020. Verfügbar unter: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4444250/ .

Gijon-Nogueron G, Soler-Crespo FJ, Sanchez-Rodriguez R, Cabello-Marique D, Lopezosa-Reca E, Ortega-Avila AB. Influence of speed and heel-to-toe drop in running shoes for female recreational runners: A cross-sectional study. Medicine. 2019;98(19):e15649.

Horvais N, Samozino P. Effect of midsole geometry on foot-strike pattern and running kinematics. Footwear Sci. 2013;5(2):81–9.

Yu P, He Y, Gu Y, Liu Y, Xuan R, Fernandez J. Acute Effects of Heel-to-Toe Drop and Speed on Running Biomechanics and Strike Pattern in Male Recreational Runners: Application of Statistical Nonparametric Mapping in Lower Limb Biomechanics. Front Bioeng Biotechnol. 2022;9:821530.

TenBroek TM, Rodrigues P, Frederick EC, Hamill J. Effects of unknown footwear midsole thickness on running kinematics within the initial six minutes of running. Footwear Sci. 2013;5(1):27–37.

TenBroek TM, Rodrigues PA, Frederick EC, Hamill J. Midsole Thickness Affects Running Patterns in Habitual Rearfoot Strikers During a Sustained Run. J Appl Biomech. 2014;30(4):521–8.

Hannigan JJ, Pollard CD. Differences in running biomechanics between a maximal, traditional, and minimal running shoe. J Sci Med Sport. 2020;23(1):15–9.

Richert FC, Stein T, Ringhof S, Stetter BJ. The effect of the heel-to-toe drop of standard running shoes on lower limb biomechanics. Footwear Sci. 2019;11(3):161–70.

Besson T, Morio C, Millet GY, Rossi J. Influence of shoe drop on running kinematics and kinetics in female runners. Eur J Sport Sci. 2019;19(10):1320–7.

Chambon N, Delattre N, Berton E, Guéguen N, Rao G. The effect of shoe drop on running pattern. Comput Methods Biomech Biomed Engin. 2013;16(sup1):97–8.

Law MHC, Choi EMF, Law SHY, Chan SSC, Wong SMS, Ching ECK, et al. Effects of footwear midsole thickness on running biomechanics. J Sports Sci. 2018;37(9):1004–10.

Chambon N, Delattre N, Guéguen N, Berton E, Rao G. Is midsole thickness a key parameter for the running pattern? Gait Posture. 2014;40(1):58–63.

Besson T, Morio C, Rossi J. Effects of shoe drop on running mechanics in women. Comput Methods Biomech Biomed Engin. 2017;20(sup1):S19-20.

Mo S, Lam WK, Ching ECK, Chan ZYS, Zhang JH, Cheung RTH. Effects of heel-toe drop on running biomechanics and perceived comfort of rearfoot strikers in standard cushioned running shoes. Footwear Sci. 2020;12(2):91–9.

Bates BT, James SL, Osternig LR. Foot function during the support phase of running. Running. 1978;3(4):24–31.

Cavanagh PR. The running shoe book. Mountain View, CA: Anderson World Inc; 1980.

Mousavi SH, Hijmans JM, Rajabi R, Diercks R, Zwerver J, van der Worp H. Kinematic risk factors for lower limb tendinopathy in distance runners: A systematic review and meta-analysis. Gait Posture. 2019;69:13–24.

Clarke TE, Frederick EC, Hamill CL. The effects of shoe design parameters on rearfoot control in running. Med Sci Sports Exerc. 1983;15(5):376–81.

Mai P, Robertz L, Thelen M, Weir G, Trudeau MB, Hamill J, et al. A method to quantify stiffness across the entire surface of a shoe‘s midsole. Footwear Sci. 2021;1–12.

Lilley K, Stiles V, Dixon S. The influence of motion control shoes on the running gait of mature and young females. Gait Posture. 2013;37(3):331–5.

Cheung RT, Ng GY. Efficacy of motion control shoes for reducing excessive rearfoot motion in fatigued runners. Phys Ther Sport. 2007;8(2):75–81.

Weir G, Willwacher S, Trudeau MB, Wyatt H, Hamill J. The Influence of Prolonged Running and Footwear on Lower Extremity Joint Stiffness. Med Sci Sports Exerc. 2020;52(12):2608–14.

Nigg BM, Stergiou P, Cole G, Stefanyshyn D, M??Ndermann A, Humble N. Effect of Shoe Inserts on Kinematics, Center of Pressure, and Leg Joint Moments during Running. Med Sci Sports Exerc. 2003;35(2):314–9.

Mündermann A, Nigg BM, Neil Humble R, Stefanyshyn DJ. Foot orthotics affect lower extremity kinematics and kinetics during running. Clin Biomech. 2003;18(3):254–62.

Mündermann A, Nigg BM, Neil Humble R, Stefanyshyn DJ. Orthotic Comfort Is Related to Kinematics, Kinetics, and EMG in Recreational Runners. Med Sci Sports Exerc. 2003;35(10):1710–9.

Kosonen J, Kulmala JP, Müller E, Avela J. Effects of medially posted insoles on foot and lower limb mechanics across walking and running in overpronating men. J Biomech. 2017;54:58–63.

Brauner T, Sterzing T, Gras N, Milani T. Small changes in the varus alignment of running shoes allow gradual pronation control. Footwear Sci. 2009;1(2):103–10.

Lewinson RT, Worobets JT, Stefanyshyn DJ. Knee abduction angular impulses during prolonged running with wedged insoles. Proc Inst Mech Eng H. 2013;227(7):811–4.

Boldt AR, Willson JD, Barrios JA, Kernozek TW. Effects of Medially Wedged Foot Orthoses on Knee and Hip Joint Running Mechanics in Females With and Without Patellofemoral Pain Syndrome. J Appl Biomech. 2013;29(1):68–77.

Rodrigues P, Chang R, TenBroek T, Hamill J. Medially posted insoles consistently influence foot pronation in runners with and without anterior knee pain. Gait Posture. 2013;37(4):526–31.

Dixon SJ, McNally K. Influence of orthotic devices prescribed using pressure data on lower extremity kinematics and pressures beneath the shoe during running. Clin Biomech. 2008;23(5):593–600.

Perry S, Lafortune M. Influences of inversion/eversion of the foot upon impact loading during locomotion. Clin Biomech. 1995;10(5):253–7.

Braga UM, Mendonça LD, Mascarenhas RO, Alves COA, Filho RGT, Resende RA. Effects of medially wedged insoles on the biomechanics of the lower limbs of runners with excessive foot pronation and foot varus alignment. Gait Posture. 2019;74:242–9.

Milani TL, Schnabel G, Hennig EM. Rearfoot motion and pressure distribution patterns during running in shoes with varus and valgus wedges. J Appl Biomech. 1995;11(2):177–87.

Lewinson RT, Wiley JP, Humble RN, Worobets JT, Stefanyshyn DJ. Altering Knee Abduction Angular Impulse Using Wedged Insoles for Treatment of Patellofemoral Pain in Runners: A Six-Week Randomized Controlled Trial. Trumbower RD, Herausgeber. PLoS ONE. 2015;10(7):e0134461.

Lewinson RT, Fukuchi CA, Worobets JT, Stefanyshyn DJ. The Effects of Wedged Footwear on Lower Limb Frontal Plane Biomechanics During Running. Clin J Sport Med. 2013;23(3):208–15.

Zhang X, Lam WK, Vanwanseele B. Dose-response effects of forefoot and arch orthotic components on the center of pressure trajectory during running in pronated feet. Gait Posture. 2022;92:212–7.

Ker RF, Bennett MB, Bibby SR, Kester RC, Alexander RM. The spring in the arch of the human foot. Nature. 1987;325(6100):147–9.

Scholz T, Zech A, Wegscheider K, Lezius S, Braumann KM, Sehner S, et al. Reliability and Correlation of Static and Dynamic Foot Arch Measurement in a Healthy Pediatric Population. J Am Podiatr Med Assoc. 2017;107(5):419–27.

Williams DS, McClay IS, Hamill J, Buchanan TS. Lower extremity kinematic and kinetic differences in runners with high and low arches. J Appl Biomech. 2001;17(2):153–63.

Salles AS, Gyi DE. An evaluation of personalised insoles developed using additive manufacturing. J Sports Sci. 2013;31(4):442–50.

Butler RJ, Davis IS, Hamill J. Interaction of Arch Type and Footwear on Running Mechanics. Am J Sports Med. 2006;34(12):1998–2005.

Butler RJ, Hamill J, Davis I. Effect of footwear on high and low arched runners’ mechanics during a prolonged run. Gait Posture. 2007;26(2):219–25.

Rice HM, Jamison ST, Davis IS. Footwear Matters: Influence of Footwear and Foot Strike on Load Rates during Running. Med Sci Sports Exerc. 2016;48(12):2462–8.

Donoghue OA, Harrison AJ, Laxton P, Jones RK. Orthotic control of rear foot and lower limb motion during running in participants with chronic Achilles tendon injury. Sports Biomech. 2008;7(2):194–205.

Nigg BM, Bahlsen HA. Influence of Heel Flare and Midsole Construction on Pronation Supination and Impact Forces for Heel-Toe Running. Int J Sport Biomech. 1988;4(3):205–19.

Stacoff A, Reinschmidt C, Nigg BM, van den Bogert AJ, Lundberg A, Denoth J, et al. Effects of shoe sole construction on skeletal motion during running. Med Sci Sports Exerc. 2001;33(2):311–9.

Liu ZL, Lam WK, Zhang X, Vanwanseele B, Liu H. Influence of heel design on lower extremity biomechanics and comfort perception in overground running. J Sports Sci. 2020;1–7.

Nigg BM, Morlock M. The influence of lateral heel flare of running shoes on pronation and impact forces. Med Sci Sports Exerc. 1987;19(3):294–302.

Sterzing T, Thomsen K, Ding R, Cheung JTM. Running shoe crash-pad design alters shoe touchdown angles and ankle stability parameters during heel–toe running. Footwear Sci. 2015;7(2):81–93.

Jafarnezhadgero AA, Sorkhe E, Oliveira AS. Motion-control shoes help maintaining low loading rate levels during fatiguing running in pronated female runners. Gait Posture. 2019;73:65–70.

Heidenfelder J, Sterzing T, Milani TL. Systematically modified crash-pad reduces impact shock in running shoes. Footwear Sci. 2010;2(2):85–91.

Bojsen-Møller F, Lamoreux L. Significance of free-dorsiflexion of the toes in walking. Acta Orthop Scand. 1979;50(4):471–9.

Trama R, Blache Y, Hautier C. Effect of rocker shoes and running speed on lower limb mechanics and soft tissue vibrations. J Biomech. 2019;82:171–7.

Sobhani S, van den Heuvel E, Bredeweg S, Kluitenberg B, Postema K, Hijmans JM, et al. Effect of rocker shoes on plantar pressure pattern in healthy female runners. Gait Posture. 2014;39(3):920–5.

Sobhani S, van den Heuvel ER, Dekker R, Postema K, Kluitenberg B, Bredeweg SW, et al. Biomechanics of running with rocker shoes. J Sci Med Sport. 2017;20(1):38–44.

Worobets JT, Panizzolo F, Hung S, Wannop JW, Stefanyshyn DJ. Increasing Running Shoe Traction can Enhance Performance. Res J Textile Apparel. 2014;18(2):17–22.

Willwacher S, Fischer KM, Dill S, Schrödter E, Trudeau MB, Rohr E, et al. Footwear effects on free moment application in running. Footwear Sci. 2018;10(1):57–68.

Thompson AT, Zipfel B, Muzigaba M, Aldous CM. Flexion location of the first metatarsophalangeal joint and the location of forefoot bend in general purpose women’s footwear. Foot Ankle Surg. 2019;25(3):340–7.

Chan MS, Huang SL, Shih Y, Chen CH, Shiang TY. Shear cushions reduce the impact loading rate during walking and running. Sports Biomech. 2013;12(4):334–42.

Miller JE, Nigg BM, Liu W, Stefanyshyn DJ, Nurse MA. Influence of foot, leg and shoe characteristics on subjective comfort. Foot Ankle Int. 2000;21(9):759–67.

Luo G, Stergiou P, Worobets J, Nigg B, Stefanyshyn D. Improved footwear comfort reduces oxygen consumption during running. Footwear Sci. 2009;1(1):25–9.

Stefanyshyn DJ, Nigg BM. Mechanical energy contribution of the metatarsophalangeal joint to running and sprinting. J Biomech. 1997;30(11–12):1081–5.

Roy JPR, Stefanyshyn DJ. Shoe Midsole Longitudinal Bending Stiffness and Running Economy, Joint Energy, and EMG. Med Sci Sports Exerc. 2006;38(3):562–9.

Willwacher S, König M, Potthast W, Brüggemann GP. Does specific footwear facilitate energy storage and return at the metatarsophalangeal joint in running? J Appl Biomech. 2013;29(5):583–92.

Willwacher S, König M, Braunstein B, Goldmann JP, Brüggemann GP. The gearing function of running shoe longitudinal bending stiffness. Gait Posture. 2014;40(3):386–90.

Oh K, Park S. The bending stiffness of shoes is beneficial to running energetics if it does not disturb the natural MTP joint flexion. J Biomech. 2017;53:127–35.

Does an increase in energy return and/or longitudinal bending stiffness shoe features reduce the energetic cost of running? | SpringerLink. Zitiert 26. Mai 2021. Verfügbar unter: https://link.springer.com/article/10.1007%2Fs00421-018-4038-1 .

Chen CH, Tu KH, Liu C, Shiang TY. Effects of forefoot bending elasticity of running shoes on gait and running performance. Hum Mov Sci. 2014;38:163–72.

Hoogkamer W, Kipp S, Frank JH, Farina EM, Luo G, Kram R. A Comparison of the Energetic Cost of Running in Marathon Racing Shoes. Sports Med. 2018;48(4):1009–19.

Day E, Hahn M. Optimal footwear longitudinal bending stiffness to improve running economy is speed dependent. Footwear Sci. 2020;12(1):3–13.

Fu F, Levadnyi I, Wang J, Xie Z, Fekete G, Cai Y, et al. Effect of the Construction of Carbon Fiber Plate Insert to Midsole on Running Performance. Materials (Basel). 2021;14(18):5156.

Flores N, Delattre N, Berton E, Rao G. Does an increase in energy return and/or longitudinal bending stiffness shoe features reduce the energetic cost of running? Eur J Appl Physiol. 2019;119(2):429–39.

Healey LA, Hoogkamer W. Longitudinal bending stiffness does not affect running economy in Nike Vaporfly Shoes. J Sport Health Sci. 2021 [zitiert 21. April 2022]; Verfügbar unter: https://www.sciencedirect.com/science/article/pii/S2095254621000739 .

Cigoja S, Firminger CR, Asmussen MJ, Fletcher JR, Edwards WB, Nigg BM. Does increased midsole bending stiffness of sport shoes redistribute lower limb joint work during running? J Sci Med Sport. 2019;22(11):1272–7.

Hunter I, McLeod A, Valentine D, Low T, Ward J, Hager R. Running economy, mechanics, and marathon racing shoes. J Sports Sci. 2019;37(20):2367–73.

Nigg BM, Cigoja S, Nigg SR. Teeter-totter effect: a new mechanism to understand shoe-related improvements in long-distance running. Br J Sports Med. 2020;bjsports:2020–102550.

Wunderlich RE, Cavanagh PR. Gender differences in adult foot shape: implications for shoe design: Med Sci Sports Exerc. 2001;605–11.

Onodera AN, Roveri MI, Oliveira WR, Sacco ICN. The influence of shoe upper construction on the plantar pressure distribution during running. Footwear Sci. 2015;7(sup1):S81-2.

Hagen M, Feiler M, Rohrand P, Hennig E. Comfort and stability ratings of different shoe lacing patterns depend on the runners’ level of performance. Footwear Sci. 2011;3(sup1):S64–6.

Hong Y, Wang L, Li JX, Zhou JH. Changes in running mechanics using conventional shoelace versus elastic shoe cover. J Sports Sci. 2011;29(4):373–9.

Ferrandis R, García AC, Ramiro J, Hoyos JV, Vera P. Rearfoot Motion and Torsion in Running: The Effects of Upper Vamp Stabilizers. J Appl Biomech. 1994;10(1):28–42.

Hagen M, Hömme AK, Umlauf T, Hennig EM. Effects of different shoe lacing patterns on perceptual variables and dorsal pressure distribution in heel-toe running. J Foot Ankle Res. 2008;1(1):O13.

Article   PubMed Central   Google Scholar  

Hagen M, Hömme AK, Umlauf T, Hennig EM. Effects of Different Shoe-Lacing Patterns on Dorsal Pressure Distribution During Running and Perceived Comfort. Res Sports Med. 2010;18(3):176–87.

Willwacher S, Kurz M, Robbin J, Thelen M, Hamill J, Kelly L, et al. Running related biomechanical risk factors for overuse injuries in distance runners: A systematic review considering injury specificity and the potentials for future research. medRxiv. 2021;2021.07.23.21261034.

Nielsen RO, Bertelsen ML, Møller M, Hulme A, Windt J, Verhagen E, et al. Training load and structure-specific load: applications for sport injury causality and data analyses. Br J Sports Med. 2018;52(16):1016–7.

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Acknowledgements

We thank Steve (Tuan) Bui, Advanced Footwear Designer, Brooks Sports Inc., for the drawing in Fig. 2 .

Open Access funding enabled and organized by Projekt DEAL. No funding sources were used to assist in the preparation of this article.

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Patrick Mai, Leon Robertz, Kevin Bill & Steffen Willwacher

Institute for Advanced Biomechanics and Motion Studies, Offenburg University, Offenburg, Germany

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Department of Physical Performance, Norwegian School of Sports Sciences, Oslo, Norway

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Biomechanics Laboratory, University of Massachusetts Amherst, Amherst, MA, USA

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Sports Tech Research Centre, Mid Sweden University, Östersund, Sweden

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Matthieu B. Trudeau

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All authors contributed to the conception, design, and formulation of the scoping review protocol. SW, MK, and PM created the search strategy. JR, MK, LR, KB, and PM conducted screening and data charting. PM and SW wrote the first draft of the manuscript. JH, GW, MBT, and KH contributed to data interpretation. All authors revised the original manuscript and approved the final manuscript.

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Supplementary Information

Additional file 1..

Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) Checklist.

Additional file 2:

Supplementary Materials Appendix 2. Search strings.

Additional file 3:

Table 1. Summary of the study characteristics, publication details, population details, data collection protocol, covariates, and biomechanical outcome variables for midsole hardness and cushioning modifications with a detailed description of the footwear studied. Table 2. Summary of the study characteristics, publication details, population details, data collection protocol, covariates, and biomechanical outcome variables for midsole geometrical modifications (heel-toe drop and midsole thickness) with a detailed description of the footwear studied. Table 3. Summary of the study characteristics, publication details, population details, data collection protocol, covariates, and biomechanical outcome variables for postings with a detailed description of the footwear studied. Table 4. Summary of the study characteristics, publication details, population details, data collection protocol, covariates, and biomechanical outcome variables for wedges with a detailed description of the footwear studied. Table 5. Summary of the study characteristics, publication details, population details, data collection protocol, covariates, and biomechanical outcome variables for arch support systems with a detailed description of the footwear studied. Table 6. Summary of the study characteristics, publication details, population details, data collection protocol, covariates, and biomechanical outcome variables for heel flare modifications with a detailed description of the footwear studied. Table 7. Summary of the study characteristics, publication details, population details, data collection protocol, covariates, and biomechanical outcome variables for crash pad with a detailed description of the footwear studied. Table 8. Summary of the study characteristics, publication details, population details, data collection protocol, covariates, and biomechanical outcome variables for rocker modifications with a detailed description of the footwear studied. Table 9. Summary of the study characteristics, publication details, population details, data collection protocol, covariates, and biomechanical outcome variables for flex grooves modificaions with a detailed description of the footwear studied. Table 10. Summary of the study characteristics, publication details, population details, data collection protocol, covariates, and biomechanical outcome variables for longitudinal bending stiffness and flexibility modificaions with a detailed description of the footwear studied. Table 11. Summary of the study characteristics, publication details, population details, data collection protocol, covariates, and biomechanical outcome variables for upper modificaions with a detailed description of the footwear studied. Table 12. Summary of the study characteristics, publication details, population details, data collection protocol, covariates, and biomechanical outcome variables for lacing modificaions with a detailed description of the footwear studied.

Additional file 4: Table 1S.

Running-related biomechanical risk factors and their level of evidence for different types of overuse injuries identified by Willwacher et al. [ 15 ]. Arrows pointing upwards indicate that an elevation of the biomechanical risk factor is associated with a specific overuse injury, arrows pointing downwards interpreted vice versa. Bolded biomechanical risk factors were identified in prospective studies; at least two independent retrospective studies identified unbolded biomechanical risk factors. A detailed description of the biomechanical risk factors is provided below the table.

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Mai, P., Robertz, L., Robbin, J. et al. Towards functionally individualised designed footwear recommendation for overuse injury prevention: a scoping review. BMC Sports Sci Med Rehabil 15 , 152 (2023). https://doi.org/10.1186/s13102-023-00760-x

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Received : 16 December 2022

Accepted : 25 October 2023

Published : 11 November 2023

DOI : https://doi.org/10.1186/s13102-023-00760-x

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