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Systematic Reviews: Introduction

What is a systematic review?

Systematic reviews seek to collate evidence that fits pre-specified eligibility criteria in order to answer a specific research question. They aim to minimize bias by using explicit, systematic methods documented in advance with a protocol.



Chandler J, Cumpston M, Thomas J, Higgins JPT, Deeks JJ, Clarke MJ. Chapter I: Introduction. In: Higgins JPT, Thomas J, Chandler J, Cumpston M, Li T, Page MJ, Welch VA (editors). Cochrane Handbook for Systematic Reviews of Interventions version 6.2 (updated February 2021). Cochrane, 2021. Available from

Why do we need Systematc Reviews?

Steps for a Systematic Review

  1. Define your question

  2. Is there a recent review relevant to your question?

  3. Develop your protocol to include inclusion, exclusion criteria and eligibility

  4. Build your search strategy

  5. Search the literature

  6. Select and critique studies

  7. Extract and synthesize data

  8. Analyse and present results

  9. Interpret results and draw conclusions

  10. Improve and update the review


Cochrane Handbook for Systematic Reviews of Interventions sets out each step of the review and the Cochrane principles can also be applied to non Cochrane reviews.

MECIR (Methodological Expectations for Cochrane Intervention Reviews) standards for reviews, updates and protocols to comply with.

PRESS (Peer Review of Electronic Search Strategies) - guidelines for evaluating electronic search strategies.

PRISMA (Preferred Reporting Items for Systematic Reviews and Meta Analyses). PRISMA 2020 statement: updated guidelines.