Welcome!
This guide is intended to provide general information and resources related to evidence synthesis projects, including systematic reviews, meta-analyses, and other types of reviews. Note that this is not an exhaustive guide nor does it capture the entirety of the rigorous methodologies utilized in these types of projects. We encourage you to contact your liaison librarian when embarking on this kind of research.
Students: Are You Conducting a Review Using Systematic Methods?
Are you an undergraduate or graduate student conducting a high-level literature review for an capstone project, thesis, or other work? We strongly recommend reviewing these student-specific guides to projects that are similar to systematic reviews, but rely on shorter timelines or searching and screening by a single person:
This planning worksheet created by librarians from Cornell University can help describe the steps you should take to conduct your review in a systematic way:
- Planning Worksheet for Structured Literature ReviewsOne-stop guide to planning and conducting a rigorous literature review.
What is evidence synthesis?
According to the Royal Society, evidence synthesis is "the process of bringing together information from a range of sources and disciplines to inform debates and decisions on specific issues" (Royal Society, 2018). These differ from traditional literature or narrative reviews in that they include a comprehensive and reproducible synthesis of research on a topic. Popular forms of evidence synthesis projects include systematic reviews, scoping reviews, and meta-analyses.
One commonly used form of evidence synthesis is a systematic review. This table compares a traditional literature review with a systematic review.
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Traditional Literature Review |
Systematic Review |
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Review Question/Topic |
Topics may be broad in scope; the goal of the review may be to place one's own research within the existing body of knowledge, or to gather information that supports a particular viewpoint. |
Starts with a well-defined research question to be answered by the review. Reviews are conducted with the aim of finding all existing evidence in an unbiased, transparent, and reproducible way. |
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Searching for Studies |
Searches may be ad hoc and based on what the author is already familiar with. Searches are not exhaustive or fully comprehensive. |
Attempts are made to find all existing published and unpublished literature on the research question. The process is well-documented and reported. |
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Study Selection |
Often lack clear reasons for why studies were included or excluded from the review. |
Reasons for including or excluding studies are explicit and informed by the research question. |
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Assessing the Quality of Included Studies |
Often do not consider study quality or potential biases in study design. |
Systematically assesses risk of bias of individual studies and overall quality of the evidence, including sources of heterogeneity between study results. |
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Synthesis of Existing Research |
Conclusions are more qualitative and may not be based on study quality. |
Bases conclusion on quality of the studies and provide recommendations for practice or to address knowledge gaps. |
Types of Reviews
Evidence synthesis projects can be very time intensive, depending on the rigor of the review method selected. Explore the resources below to determine what type of review may be best suited to your research question.
- What type of review is right for you?Developed by Cornell University Library, this decision tree helps identify key steps and features of various review types to help you determine which is best suited to your research question.
- Temple University: Review TypesExplore a dozen review types by navigating the tabs on the left side of the screen of this guide developed by Temple University Libraries.
- Meeting the review family: Exploring review types and associated information retrieval requirements (Sutton, Clowes, Preston, & Booth, 2019)This Health Information and Libraries Journal article defines health-related review methodologies and outlines appropriate search methods for conducting them.
- Rethinking systematic literature reviews as the gold standard for interdisciplinary topics (Drake, Reid, & Savage, 2021)This study explores systematic literature review methodology and determines that they "can be messy and limiting" for a variety of reasons (p. 27).
Explore Existing Reviews
Searching for existing reviews on a topic related to your own research question can be a good place to start. These reviews may provide a model for approaching your own review of the literature, including recommended search strategies and resources.
- Campbell Systematic Reviews
An open access journal prepared under the editorial control of the Campbell Collaboration. The journal publishes systematic reviews, evidence and gap maps, and methods research papers. Topic areas include: Ageing; Business and Management; Climate Solutions; Crime and Justice; Disability; Education; International Development; Knowledge Translation and Implementation; Methods; Nutrition and Food Security; Sexual Orientation and Gender Identity; Social Welfare; and Training. - JBI Evidence Synthesis
Publishes systematic and scoping review protocols, diverse types of systematic reviews, and scoping reviews covering multi-disciplinary healthcare-related topics that follow methodology and methods developed by the Joanna Briggs Institute. The journal also publishes editorials, letters to the editor as well as original applied research and discussion papers examining synthesis methods. - Systematic Reviews journalSystematic Reviews encompasses all aspects of the design, conduct and reporting of systematic reviews. The journal publishes high quality systematic review products including systematic review protocols, systematic reviews related to a very broad definition of health, rapid reviews, updates of already completed systematic reviews, and methods research related to the science of systematic reviews, such as decision modelling.
- Cochrane LibraryThe Cochrane Library is a collection of six databases that contain different types of high-quality, independent evidence to inform healthcare decision-making, and a seventh database that provides information about Cochrane groups. Databases included are Cochrane Database of Systematic Reviews (CDSR), Cochrane Central Register of Controlled Trials (CENTRAL), Cochrane Methodology Register (CMR), Database of Abstracts of Reviews of Effects (DARE), Health Technology Assessment Database (HTA) and NHS Economic Evaluation Database (EED). Find more information.
- The Guide to Community Preventative ServicesThe Community Guide is a website that houses the official collection of all Community Preventive Services Task Force (Task Force) findings and the systematic reviews on which they are based.
- IES: What Works ClearinghousePart of the U.S. Department of Education's National Center for Education Evaluation and Research Assistance, the Institute of Education Sciences' (IES) What Works Clearinghouse is a central and trusted source of scientific evidence on education programs, products, practices, and policies. It reviews research, determines which studies meet rigorous standards, and summarizes the findings with a focus on high-quality research to answer the question, “What works in education?”