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Systematic Reviews

Information on how to conduct systematic reviews in the health sciences.

Choosing a Review Type

This guide focuses on the methodology for systematic reviews (SRs), but an SR may not be the best methodology to use to meet your project's goals. Use the articles listed here or in the Types of Literature Reviews box below for information about additional methodologies that could better fit your project. 

Types of Literature Reviews

Systematic Reviews

  • With a clearly defined question,
    • systematically and transparently searches for a broad range of information to synthesize, in order to find the effect of an intervention.
    • uses a protocol 
    • has a clear data extraction and management plan.
  • Time-intensive and often take months to a year or more to complete, even with a multi-person team. 

NOTE: The term "systematic review" is also used incorrectly as a blanket term for other types of reviews.

Methodological Guidance

For issues in systematic reviews, especially in social science or other qualitative research: 


  • Lescoat, A., Murphy, S. L., Roofeh, D., et al. (2021). Considerations for a combined index for limited cutaneous systemic sclerosis to support drug development and improve outcomes.
  • DeLong, M. R., Tandon, V. J., Bertrand, A. A. (2021). Review of Outcomes in Prepectoral Prosthetic Breast Reconstruction with and without Surgical Mesh Assistance.
  • Carey, M. R., Vaughn, V. M., Mann, J. (2020). Is Non-Steroidal Anti-Inflammatory Therapy Non-Inferior to Antibiotic Therapy in Uncomplicated Urinary Tract Infections: a Systematic Review.


  • Statistical technique for combining the findings from disparate quantitative studies.
  • Uses statistical methods to objectively evaluate, synthesize, and summarize results.
  • May be conducted independently or as part of a systematic review.

Methodological Guidance


  • Bauer, M. E., Toledano, R. D., Houle, T., et al. (2020). Lumbar neuraxial procedures in thrombocytopenic patients across populations: A systematic review and meta-analysis.
  • Mailoa J, Lin GH, Khoshkam V, MacEachern M, et al. Long-Term Effect of Four Surgical Periodontal Therapies and One Non-Surgical Therapy: A Systematic Review and Meta-Analysis.

Umbrella Reviews

  • Reviews other systematic reviews on a topic. 
  • Often defines a broader question than is typical of a traditional systematic review.
  • Most useful when there are competing interventions to consider.

Methodological Guidance


  • Gastaldon, C., Solmi, M., Correll, C. U., et al. (2022). Risk factors of postpartum depression and depressive symptoms: umbrella review of current evidence from systematic reviews and meta-analyses of observational studies.
  • Blodgett, T. J., & Blodgett, N. P. (2021). Melatonin and melatonin-receptor agonists to prevent delirium in hospitalized older adults: An umbrella review.

Comparative effectiveness 

  • Systematic reviews of existing research on the effectiveness, comparative effectiveness, and comparative harms of different health care interventions.
  •  Intended to provide relevant evidence to inform real-world health care decisions for patients, providers, and policymakers.

Methodological Guidance


  • Tanni KA, Truong CB, Johnson BS, Qian J. Comparative effectiveness and safety of eribulin in advanced or metastatic breast cancer: a systematic review and meta-analysis. Crit Rev Oncol Hematol. 2021 Jul;163:103375. doi: 10.1016/j.critrevonc.2021.103375. Epub 2021 Jun 2. PMID: 34087344.
  • Rice D, Corace K, Wolfe D, Esmaeilisaraji L, Michaud A, Grima A, Austin B, Douma R, Barbeau P, Butler C, Willows M, Poulin PA, Sproule BA, Porath A, Garber G, Taha S, Garner G, Skidmore B, Moher D, Thavorn K, Hutton B. Evaluating comparative effectiveness of psychosocial interventions adjunctive to opioid agonist therapy for opioid use disorder: A systematic review with network meta-analyses. PLoS One. 2020 Dec 28;15(12):e0244401. doi: 10.1371/journal.pone.0244401. PMID: 33370393; PMCID: PMC7769275.

Scoping Review or Evidence Map

  • Systematically and transparently collect and categorize existing evidence on a broad question of policy or management importance.

  • Seeks to identify research gaps and opportunities for evidence synthesis rather than searching for the effect of an intervention. 

  • May critically evaluate existing evidence, but does not attempt to synthesize the results in the way a systematic review would. (see EE Journal and CIFOR)

  • May take longer than a systematic review.

  • For useful guidance on whether to conduct a scoping review or not, see Figure 1 in this article. Pollock, D, Davies, EL, Peters, MDJ, et al. Undertaking a scoping review: A practical guide for nursing and midwifery students, clinicians, researchers, and academics. J Adv Nurs. 2021; 77: 21022113. a helpful

Methodological Guidance


  • Bouldin E, Patel SR, Tey CS, et al. Bullying and Children who are Deaf or Hard-of-hearing: A Scoping Review.

  • Finn M, Gilmore B, Sheaf G, Vallières F. What do we mean by individual capacity strengthening for primary health care in low- and middle-income countries? A systematic scoping review to improve conceptual clarity.

  • Hirt J, Nordhausen T, Meichlinger J, Braun V, Zeller A, Meyer G. Educational interventions to improve literature searching skills in the health sciences: a scoping review.


Rapid Review

  • Useful for addressing issues needing timely decisions, such as developing policy recommendations. 

  • Applies systematic review methodology within a time-constrained setting.

  • Employs intentional, methodological "shortcuts" (limiting search terms for example) at the risk of introducing bias.

  • Defining characteristic is the transparency of team methodological choices.

Methodological Guidance


  • Norris HC, Richardson HM, Benoit MC, et al. (2021) Utilization Impact of Cost-Sharing Elimination for Preventive Care Services: A Rapid Review.

  • Marcus N, Stergiopoulos V. Re-examining mental health crisis intervention: A rapid review comparing outcomes across police, co-responder and non-police models. Health Soc Care Community. 2022 Feb 1. doi: 10.1111/hsc.13731. Epub ahead of print. PMID: 35103364.

Narrative (Literature) Review

  • A broad term referring to reviews with a wide scope and non-standardized methodology.

    • See Baethge 2019 below for a method to provide quality assessment,

  • Search strategies, comprehensiveness, and time range covered will vary and do not follow an established protocol.

  • It provides insight into a particular topic by critically examining sources, generally over a particular period of time.

Methodological Guidance


  • Czypionka, T., Greenhalgh, T., Bassler, D., & Bryant, M. B. (2021). Masks and Face Coverings for the Lay Public : A Narrative Update.
  • Gardiner, F. W., Nwose, E. U., Bwititi, P. T., et al.. (2017). Services aimed at achieving desirable clinical outcomes in patients with chronic kidney disease and diabetes mellitus: A narrative review.
  •  Dickerson, S. S., Connors, L. M., Fayad, A., & Dean, G. E. (2014). Sleep-wake disturbances in cancer patients: narrative review of literature focusing on improving quality of life outcomes.