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Br J Gen Pract. 2007 May 1; 57(538): 425.
PMCID: PMC2047040

Tips and tricks in performing a systematic review

CHAPTER 1

Why do, and what to do when starting a systematic review

Frequently people ask what is a systematic review, what is the point, how does it differ from a normal literature review or meta-analysis, and what is the first thing I do to get started?

To address the first point, a systematic review is: a systematic search of literature through designated and clearly defined sources, followed by systematic data analysis and explanation. It differs from a literature review because a literature review may only include articles that the author(s) know about and that support their beliefs. Therefore, the systematic review is supposed to be an unbiased and replicable representation of current knowledge with reference to a particular topic.

The purpose of a systematic review can be considered to be twofold:

  • to gather all existing knowledge and influence policy, process, and practice; and
  • to generate hypotheses which need further research.

The process that follows is nearly identical for each type of review.

The first step is to outline your research question, and identify the knowledge you are looking to gather. Step two is to conduct some unsystematic research to check that a review does not already exist. The best places to look for a review are in databases that only have reviews: for example, the Cochrane Database of Systematic Reviews (CDSR); Centre for Reviews and Dissemination (CRD); and Joanna Briggs Institute (JBI). If you are unable to find any completed reviews the CRD has a register of ongoing reviews. And if you still can not find any reviews have a ‘quick’ look on www.pubmed.gov using the review and meta-analyses limits.

If you find a systematic review in the relevant area, look to see if:

  • it directly answers your question;
  • when it was implemented, as many reviews need updating; and
  • if it is a good quality review.

To assess its quality read the QUORUM statement, which defines what a high quality systematic review should entail.1

If you still think you need to perform a review, the next step is gathering preliminary evidence (details in next month's issue of the Journal).

REFERENCES

1. Moher D, Cook DJ, Eastwood S, et al. Improving the quality of reports of meta-analyses of randomised controlled trials: the QUOROM statement. Quality of reporting of meta-analyses. Lancet. 1999;354(9193):1896–1900. [PubMed]

Articles from The British Journal of General Practice are provided here courtesy of Royal College of General Practitioners