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Systematic Reviews

What is a Systematic Review?

From the Cochrane Handbook for Systematic Reviews of Interventions:
 

"A systematic review attempts to collate all empirical evidence that fits pre-specified eligibility criteria in order to answer a specific research question. It uses explicit, systematic methods that are selected with a view to minimizing bias, thus providing more reliable findings from which conclusions can be drawn and decisions made (Antman 1992, Oxman 1993). The key characteristics of a systematic review are:

  • a clearly stated set of objectives with pre-defined eligibility criteria for studies;

  • an explicit, reproducible methodology;

  • a systematic search that attempts to identify all studies that would meet the eligibility criteria;

  • an assessment of the validity of the findings of the included studies, for example through the assessment of risk of bias; and

  • a systematic presentation, and synthesis, of the characteristics and findings of the included studies."

Higgins, Julian. Cochrane Handbook for Systematic Reviews of Interventions. Hoboken, NJ, USA: John Wiley & Sons, 2009. ProQuest ebrary.

(Source)

 

Video (2017): An Introduction to Conducting Systematic Reviews (26:46 minutes)

Andrea Goldstein Shipper
Health Sciences and Human Services Library, University of Maryland

Other Types of Reviews

Literature (Narrative) Review

  • A broad term referring to reviews with a wide scope and non-standardized methodology. 
  • Search strategies, comprehensiveness, and time range covered will vary and do not follow an established protocol.
     

​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.
  • See Arksey and O'Malley (2005) for methodological guidance.
     

​Rapid Review

  • Applies Systematic Review methodology within a time-constrained setting.
  • Employs methodological "shortcuts" (limiting search terms for example) at the risk of introducing bias.
  • Useful for addressing issues needing quick decisions, such as developing policy recommendations.
  • See Evidence Summaries: The Evolution of a Rapid Review Approach
     

Umbrella Review

  • 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.
     

Meta-analysis

  • 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.

(Source)