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Systematic Reviews - Research Guide

Systematic Reviews

What is a Systematic Review?


A systematic review analyses evidence from the literature in order to answer a  clinical research question.

An important research organisation that provides support and guidance for researchers undertaking systematic reviews is the Cochrane Collaboration. The Cochrane Handbook for Systematic Reviews of Interventions (Section 1.2) defines a systematic review as:

"A systematic review attempts to identify, appraise and synthesize all the empirical evidence that meets pre-specified eligibility criteria to answer a given research question. Researchers conducting systematic reviews use explicit methods aimed at minimizing bias, in order to produce more reliable findings that can be used to inform decision making."

A quantitative systematic review will include studies that have numerical data.
A qualitative systematic review will include data from observations, diaries, interviews, or other verbal interactions and focus on the interpretation of, and significance given to, the data collected by the participants.

Other Related Review Types

Scoping Review

Assesses emerging evidence and determines the scope of literature on a given topic. A scoping review should give a clear indication of the volume of literature and studies available, as well as an overview of the review topic. Scoping reviews are useful for examining emerging evidence when it is unclear what specific clinical questions could be posed and addressed by a systematic review.

Umbrella review

Compares and contrasts the findings of previous reviews relevant to a review question.  An umbrella review synthesises only  the highest level of evidence - other systematic reviews and meta-analyses.

Rapid review
Speeds up the systematic review process by omitting some stages of the systematic review. While less rigorous, rapid reviews provide more timely information for clinical decision making compared with standard systematic reviews.


More information on review typologies

How is a Systematic Review Different from a Literature Review?

Systematic Review Literature (or Narrative) Review

Examines a clearly defined topic or question

Provides an overview of a topic

Uses an explicit search plan or protocol to minimize bias

Does not use an explicit search protocol or plan

A comprehensive search is undertaken to identify all potentially relevant studies

The search process may or may not include all potentially relevant studies

An explicit, predetermined protocol, that specifies inclusion and exclusion criteria, is used to select studies for the review

An explicit, predetermined protocol is not used to select the studies that are used to support the reviewers' recommendations

The quality of individual studies is rigorously appraised in a meta-analysis and a systematic synthesis of the results of included studies is undertaken with evidence "grades" applied to individual studies

A level of evidence rating system may be used to "grade" the quality and strength of individual studies

Provides evidence (research)

May be evidence-based, but is not evidence (research)

When evidence is lacking, the authors usually recommend further research

When evidence is lacking, the authors make recommendations based on their opinions and experience

More information on conducting a literature review can be found in our Literature Review guide.

Examples of Reviews

Literature or Narrative Review

Abdel-Moneim, A. S. (2014). Middle East respiratory syndrome coronavirus (MERS-CoV): Evidence and speculations. Archives of Virology, 159(7), 1575-1584. doi:10.1007/s00705-014-1995-5

Systematic Review

Davlin, S.L., & VonVille, H.M. (2012). Canine rabies vaccination and domestic dog population characteristics in the developing world: A systematic review. Vaccine, 30(24), 3492-3502. doi:10.1016/j.vaccine.2012.03.069

Halton, K., Sarna, M.,Barnett, A., Leonardo, L., & Graves, N. (2013). A systematic review of community based interventions for emerging zoonotic infectious diseases in South East Asia. The JBI Library of Systematic Reviews, 11(2), 1-235.

Cochrane Review

Yamato, T. P., Maher, C. G., Saragiotto, B. T., Hancock, M. J., Ostelo, R. W. J. G., Cabral, C. N. M., ... Costa, L. O. P. (2015) Pilates for low back pain. Cochrane Database of Systematic Reviews.  doi:10.1002/14651858.CD010265.pub2

Systematic Review Protocol

Downes, M. J., Dean, R. & Bath-Hextall, F. J. (2013). Animal-assisted therapy for people with serious mental illness. The Cochrane Library.  doi: 10.1002/14651858.CD010818 

Review Article

Duclos, C., Beauregard, M.-P., Bottari, C. Ouillet, M.-C., & Gosselin, N. (2015).  The impact of poor sleep on cognition and activities of daily living after traumatic brain injury: A review. Australian Occupational Therapy Journal. 62(1), 2-12. doi: 10.1111/1440-1630.12164