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Systematic Reviews & Other Syntheses


The purpose of this guide is to connect you with useful resources for embarking on a systematic review or other type of synthesis, with a particular focus on searching for studies and managing your results.

Please note: some hyperlinked resources are provided by Queen's University Library and may not be available to non-affiliates. Queen's affiliates viewing this guide from off-site may need to login to the library's off-campus access to view the full contents of certain electronic books and articles.

Types of Syntheses

Knowledge syntheses, also known as syntheses, are rigorously conducted literature reviews of the research evidence. When systematic reviews were the first type of synthesis to appear in the health care literature back in the 1970s, the main objective was to synthesize quantitative research studies. Limitations of traditional systematic reviews and meta-analyses have led to the adaptation of syntheses to include: qualitative systematic reviews, mixed-methods reviews, rapid reviews, network meta-analyses, scoping reviews and realist reviews. While many syntheses begin with a clear question, their methodologies and the types of research evidence synthesized to answer the question can be quite different.

To help determine the most appropriate type of synthesis for your research question and purpose, you may find it helpful to consult the following:

Systematic Reviews

A systematic review attempts to identify, select, synthesize, and appraise all evidence on a given research question in a systematic and transparent manner. (Note: before embarking on a systematic review, it is important to conduct a literature search to determine whether or not a systematic review has already been published on your topic. If there is already a recent systematic review on your topic, it may be difficult to publish a similar systematic review.) To help ensure your systematic review is of high-quality, consider the criteria for assessing systematic reviews presented in the AMSTAR Checklist (A Measurement Tool to Assess Systematic Reviews). 

Introductory videos:

Systematic reviews steps: (Uman, 2011)

  1. Formulate the review question
  2. Define inclusion/exclusion criteria
  3. Develop reproducible search strategies and locate studies
  4. Select studies
  5. Extract data
  6. Assess study quality
  7. Analyze and interpret results
  8. Disseminate findings

Systematic review types:

  1. Quantitative systematic reviews include only quantitative research studies
  2. Qualitative systematic reviews include qualitative and/or mixed methods research studies
  3. Mixed methods reviews include both quantitative and qualitative studies

Most often the type of systematic review conducted will depend on the review question. For example, systematic reviews of healthcare interventions are generally quantitative reviews that include research studies in the form of randomized controlled trials. Systematic reviews of patient experiences are generally qualitative reviews that may include qualitative and mixed methods research studies. Mixed methods reviews are utilized to address the limitations of single method reviews, which are frequently too narrow in scope (Peters et al., 2015). "By including diverse forms of evidence from different types of research, mixed methods reviews attempt to maximize the findings - and the ability of those findings to inform policy and practice" (Peters et al., 2015, p. 5).

Cochrane describes five types of Cochrane Reviews:

  1. Intervention reviews assess the benefits and harms of interventions used in healthcare and health policy
  2. Diagnostic test accuracy reviews assess how well a diagnostic test performs in diagnosing and detecting a particular disease
  3. Methodology reviews address issues relevant to how systematic reviews and clinical trials are conducted and reported
  4. Qualitative reviews synthesize qualitative evidence to address questions on aspects other than effectiveness
  5. Prognosis reviews address the probable course or future outcome(s) of people with a health problem

Systematic review timeframe:

Topic: The review topic will also impact the amount of time required to conduct the review. For example, a systematic review on the effectiveness of a relatively new drug therapy may require less time to complete if the search yields a low number of results to screen and if the review itself only includes a small number of studies.

Searching: The amount of time needed to complete this component of the review will depend on: how straight-forward or complex the topic is, the number and type of resources that will be searched (refer to Where to Search), and the searcher's level of expertise. Working with an experienced librarian is highly recommended.

Review team: Estimating how long it will take to complete a systematic review will depend on the review team's availability to work on the review. Systematic review team members may have competing priorities throughout the duration of the systematic review that can delay the process.

Research evidence:

  • A research study found that the median time spent searching was just under 8 hours, including 1.5 hours spent searching the grey literature, while the average time spent searching was approximately 24 hours, of which 6.5 hours were spent searching the grey literature (Saleh et al., 2014). The average number of resources searched was 9, including grey literature resources. Grant funding influenced the amount of time spent searching and institution type impacted the number of resources searched.
  • Greenhalgh and Peacock (2005) found that: "Electronic searching, including developing and refining search strategies and adapting these to different databases, took about two weeks of specialist librarian time..." (p1065).

Scoping Reviews

"Scoping studies aim to map rapidly the key concepts underpinning a research area and the main sources and types of evidence available, and can be undertaken as stand-alone projects in their own right, especially where an area is complex or has not been reviewed comprehensively before" (Mays et al., 2001, p. 194).

The following articles describe the purpose and methods of scoping reviews in detail:

Peters, M. D., Godfrey, C. M., Khalil, H., McInerney, P., Parker, D., & Soares, C. B. (2015). Guidance for conducting systematic scoping reviews. International journal of evidence-based healthcare, 13(3), 141-146.

Peters, M., Godfrey, C., McInerney, P., Soares, C., Hanan, K., & Parker, D. (2015). The Joanna Briggs Institute Reviewers' Manual 2015: Methodology for JBI Scoping Reviews.

Library Support

It is best practice for reviewers to work with a librarian during the systematic review and knowledge synthesis process:

"Work with a librarian or other information specialist trained in performing systematic reviews to plan the search strategy." Standard 3.1.1 of Finding What Works in Health Care: Standards for Systematic Reviews (Institute of Medicine, 2011).

"Expert searchers are an important part of the systematic review team, crucial throughout the review process—from the development of the proposal and research question to publication" (McGowan & Sampson, 2005, p. 74).

Knowledge Synthesis Library Support:

Advisory consultation is available to all faculty, staff and students. Additionally, collaboration may be available to faculty, or research teams that include faculty, at the discretion of the librarian based on considerations such as whether or not a protocol for the research exists, the proposed time frame for the project, etc.

To meet with a librarian about support for your knowledge synthesis, please complete the consultation request form.

Advisory consultation services

A librarian can advise on the following:

  • A preliminary search to determine if a knowledge synthesis on the topic already exists
  • Review question formulation
  • Review steps
  • Database/resource selection for specific topics
  • Database/resource-specific search methods and techniques
  • Setting up search alerts for new publications
  • Citation management and review software
  • Search methods for locating grey literature
  • Additional methods for locating studies (searching trial registries, hand-searching, cited reference searching etc.)
  • How to obtain full-text articles via Queen’s University Library and inter-library loan (ILL)
  • How the search methods should be reported for transparency and reproducibility 

Collaboration services

Please note: the following levels of knowledge synthesis support should be negotiated up-front as to whether the librarian’s contribution will be formally recognized through manuscript acknowledgement or co-authorship.

A librarian may agree to do the following:

  • Conduct a preliminary search to determine if a knowledge synthesis on the topic already exists
  • Develop and execute database/resource-specific search strategies
  • Setup search alerts for new publications
  • Document formal, comprehensive database/resource-specific search strategies for reproducibility
  • Export search results into desired format (Excel spreadsheet, text or RIS file, etc.)
  • Import search results to citation management or review software 
  • Assist with search methods for locating grey-literature
  • Assist with additional methods for locating studies (cited reference searching, etc.)
  • Remove duplicate search results
  • Write up the search methods according to PRISMA or other appropriate guidelines



Cochrane. (n.d.). About Cochrane reviews. Retrieved May 11, 2015, from

Grant, M. J., & Booth, A. (2009). A typology of reviews: an analysis of 14 review types and associated methodologies. Health Information & Libraries Journal, 26(2), 91-108.

Greenhalgh, T., & Peacock, R. (2005). Effectiveness and efficiency of search methods in systematic reviews of complex evidence: audit of primary sources. BMJ: British Medical Journal, 331(7524), 1064-1065.

Grimshaw, J. (2010). A guide to knowledge synthesis: A knowledge synthesis chapter. Canadian Institutes of Health Research.

Higgins, J.P.T. & Green, S. (Eds.). (2011). Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 [updated March 2011]. The Cochrane Collaboration. Available from

Institute of Medicine. (2011). Finding what works in health care: standards for systematic reviews. Washington, DC: The National Academies Press.

Kastner, M., Antony, J., Soobiah, C., Straus, S. E., & Tricco, A. C. (2016). Conceptual recommendations for selecting the most appropriate knowledge synthesis method to answer research questions related to complex evidence. Journal of Clinical Epidemiology, 73, 43-49.

Mays, N., Roberts, E., & Popay, J. (2001). Synthesising research evidence. Studying the Organisation and Delivery of Health Services: Research Methods, 188-220.

McGowan, J., & Sampson, M. (2005). Systematic reviews need systematic searchers. Journal of the Medical Library Association, 93(1), 74.

Pearson, A., White, H., Bath-Hextall, F., Apostolo, J., Salmond, S., & Kirkpatrick, P. (2014). Methodology for JBI mixed methods systematic reviews. The Joanna Briggs Institute Reviewers’ Manual.
Peters, M. D., Godfrey, C. M., Khalil, H., McInerney, P., Parker, D., & Soares, C. B. (2015). Guidance for conducting systematic scoping reviews. International journal of evidence-based healthcare, 13(3), 141-146.

Peters, M. D, Godfrey, C. M., McInerney, P., Soares, C., Hanan, K., & Parker, D. (2015). The Joanna Briggs Institute Reviewers' Manual 2015: Methodology for JBI Scoping Reviews.

Petticrew, M. (2001). Systematic reviews from astronomy to zoology: myths and misconceptions. BMJ: British Medical Journal, 322(7278), 98.

Saleh, A. A., Ratajeski, M. A., & Bertolet, M. (2014). Grey literature searching for health sciences systematic reviews: a prospective study of time spent and resources utilized. Evidence Based Library and Information Practice, 9(3), 28-50.

Tricco, A. C., Lillie, E., Zarin, W., O’Brien, K., Colquhoun, H., Kastner, M., ... & Kenny, M. (2016). A scoping review on the conduct and reporting of scoping reviews. BMC medical research methodology, 16(1), 1.

Uman, L. S. (2011). Systematic reviews and meta-analyses. Journal of the Canadian Academy of Child and Adolescent Psychiatry, 20(1), 57.