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Systematic Reviews

This guide provides information and resources about systematic reviews, meta-analyses, and other literature reviews.

Breakdown of Systematic Reviews

A systematic review is a comprehensive literature review that seeks to answer a specific clinical question using existing research as evidence. According to Cook et. al (1997), systematic reviews "can help practitioners keep abreast of the medical literature by summarizing large bodies of evidence and helping to explain differences among studies on the same question."

Systematic reviews are designed to:

  • Locate all relevant published and unpublished sources of evidence
  • Specify inclusion and exclusion criteria for selected studies
  • Evaluate each selected study for quality and bias
  • Synthesize findings from selected sources of evidence without bias
  • Provide a balanced and unbiased summary of findings while accounting for flaws or limitations within the evidence

For more information on systematic reviews and meta-analyses, visit Systematic reviews and meta-analyses: a step-by-step guide by Kate McAllister.

For reporting guidelines for systematic reviews and meta-analyses, visit PRISMA Transparent Reporting of Systematic Reviews and Meta-Analyses and the Equator Network.

Systematic reviews require a significant time commitment because of their standards and methodology requirements. Systematic reviews may take a review team an estimated 9-12 months to complete.

The average timeline for a systematic review is estimated below, as outlined in the Cochrane Handbook for Systematic Reviews of Interventions 2011:

Systematic Review Timeline

Adapted from Higgins JPT, Green S (editors). Cochrane Handbook for Systematic Reviews of Interventions Version 5.1.0 [updated March 2011]. The Cochrane Collaboration, 2011. Available from handbook.cochrane.org.

Other Reviews

A meta-analysis is a type of systematic review that uses statistical methods to summarize the results of studies that meet the criteria for inclusion within the review. 

For more information on systematic reviews and meta-analyses, visit Systematic reviews and meta-analyses: a step-by-step guide by Kate McAllister.

For reporting guidelines for systematic reviews and meta-analyses, visit PRISMA Transparent Reporting of Systematic Reviews and Meta-Analyses.

For more information on analyzing data for systematic reviews, see Part 2 - Chapter 10 of the Cochrane Handbook for Systematic Reviews of Interventions.

A scoping review provides an assessment of the potential size and scope of available research on a particular topic. Similar to a systematic review, a scoping review follows a predetermined search methodology and reporting process. Scoping reviews questions are often broader than systematic review questions, as they are designed to identify the "nature and extent of research evidence (usually including ongoing research)" (Grant and Booth, 2009). Scoping reviews can highlight areas where future systematic reviews can be conducted, or be used as standalone reviews when systematic reviews are not feasible to share findings, identify research gaps and make recommendations for future research (Peters et. al, 2015).

For more information on scoping reviews, please see the following articles:

Grant, M. J., & Booth, A. (2009). A typology of reviews: an analysis of 14 review types and associated methodologies. Health Information & Libraries Journal26(2), 91-108. DOI: 10.1111/j.1471-1842.2009.00848.x. 

Peters, M. D., Godfrey, C. M., Khalil, H., McInerney, P., Parker, D., & Soares, C. B. (2015). Guidance for conducting systematic scoping reviews. JBI Evidence Implementation13(3), 141-146. DOI: 10.1097/XEB.0000000000000050. 

For reporting requirements for scoping reviews, please visit PRISMA for Scoping Reviews.

A rapid review uses systematic review methods to provide quick yet thorough assessments of existing evidence surrounding a policy or practice issue. While a rapid review is designed to be conducted in less time than a systematic review, a rapid review incorporates systematic review methods to critically appraise research finding within included studies. A rapid review may use specified techniques to shorten the review timeframe, and the reviewer(s) must specifically report which stages to limit and the likely effects of those limitations (Grant and Booth, 2009).

For more information on rapid reviews, please see the following articles:

Garritty, C., Gartlehner, G., Nussbaumer-Streit, B., King, V. J., Hamel, C., Kamel, C., Affengruber, L., & Stevens, A. (2021). Cochrane Rapid Reviews Methods Group offers evidence-informed guidance to conduct rapid reviews. Journal of clinical epidemiology130, 13–22. https://doi.org/10.1016/j.jclinepi.2020.10.007.

Grant, M. J., & Booth, A. (2009). A typology of reviews: an analysis of 14 review types and associated methodologies. Health information & libraries journal26(2), 91-108. DOI: 10.1111/j.1471-1842.2009.00848.x.

An integrative review summarizes both experimental, non-experimental, and theoretical literature to expand understanding surrounding a specific healthcare problem or phenomenon. According to Whittemore & Knafl (2005), integrative reviews have the potential to impact evidence-based practice for nursing because it is the only approach that allows for the combination of diverse methodologies.

For more information surrounding integrative reviews, please explore the following articles:

Toronto, C. E., & Remington, R. (Eds.). (2020). A step-by-step guide to conducting an integrative review. Cham, Swizterland: Springer International Publishing. 

Whittemore, R., & Knafl, K. (2005). The integrative review: updated methodology. Journal of advanced nursing52(5), 546–553. https://doi.org/10.1111/j.1365-2648.2005.03621.x 

A narrative (literature) review is a form of knowledge synthesis surrounding a specific research question or issue. A narrative review does not require a systematic search of the literature and does not require included studies to be assessed for risk or bias. According to Ferrari (2015), narrative (literature) reviews are helpful for exploring general topics or debates, addressing more than one question, and identifying knowledge gaps and areas for future research.

For more information regarding narrative (literature) reviews, please see the following articles:

Ferrari, R. (2015). Writing narrative style literature reviews. Medical writing (Leeds), 24(4), 230–235. https://doi.org/10.1179/2047480615Z.000000000329. 

Grant, M. J., & Booth, A. (2009). A typology of reviews: an analysis of 14 review types and associated methodologies. Health information & libraries journal26(2), 91-108. DOI: 10.1111/j.1471-1842.2009.00848.x. 

What Review is Right for You?