Systematic reviews

What is a systematic review?

A systematic review attempts to gather all the empirical evidence that fits pre-specified eligibility criteria 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. 

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

The following document compares elements of a systematic review and of a comprehensive literature review:


  • Higgins, J.P.T., & Green, S. (Eds.). (2011). Cochrane handbook for systematic reviews of interventions, version 5.1.0. Available from
  • Liberati, A. et al. (2009). The PRISMA statement for reporting systematic reviews and meta-analyses of studies that evaluate health care interventions: Explanation and elaboration. PLoS Medicine6(7), e1000100. doi:

Steps of a systematic review

Researchers conducting a systematic review need to follow various predetermined yet flexible and iterative stages that describe necessary steps required to produce a rigorous synthesis of the literature.

Steps include:


Acknowledgement: This guide is based on the PIECES acronym developed by M. J. Foster and S. T. Jewell in their book Assembling the PIECES of a systematic review: A guide for librarians (Lanham, MD: Rowman & Littlefield, 2017).


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