USF Shimberg Health Sciences Library

Systematic Reviews

A guide to the systematic review process.

What is a Systematic Review?

According to the Cochrane Library

"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. (See Section 1.2 in the Cochrane Handbook for Systematic Reviews of Interventions.)" About Cochrane

 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.

(Chapter 1.2.2, 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

What Are Systematic Reviews: a video from the Cochrane Consumers and Communication Group.

Timeline for a review

A systematic review is a lengthy process and you should be sure you have the time to commit to the process.  Completing the systematic review can take from 12-18 months or more!

It takes time to develop exhaustive and comprehensive searches and additional time to review the results.   Large citation retrievals (many thousand!) are possible depending on the topic.

Estimated timeline for completing a Cochrane systematic review:


          Month                   Activity

           1 – 2                   Preparation of protocol.

           3 – 8                   Searches for published and unpublished studies.

           2 – 3                   Pilot test of eligibility criteria.

           3 – 8                   Inclusion assessments.

           3                        Pilot test of ‘Risk of bias’ assessment.

           3 – 10                 Validity assessments.

           3                        Pilot test of data collection.

           3 – 10                 Data collection.

           3 – 10                 Data entry.

           5 – 11                 Follow up of missing information.

           8 – 10                 Analysis.

           1 – 11                 Preparation of review report.

           12 –                    Keeping the review up-to-date.



Source: 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 

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