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Methods@Manchester

Systematic Reviews

Prof Helen Worthington, School of Dentistry

A systemic review is a concise summary of all the best evidence on a specific question.  Systematic reviews are scientific investigations in there own right and are frequently as demanding as conducting primary research.  They synthesise the results of multiple primary investigations by using strategies that limit bias and random error.  

These strategies include a comprehensive search of all potentially relevant articles and the use of explicit, reproducible criteria in the selection of articles for review. Primary research designs and study characteristics are appraised, data are synthesised, and results are interpreted.

So how are systematic reviews different from a normal (literature) review?

Traditional literature reviews are often one individual’s opinion of the current state of knowledge.  It is always easy to find research articles to support your own point of view. This is inevitably limited and may be biased. Systematic review are undertaken with rigorous methodology to avoid this.

What can a systematic review offer?

Combining results can increase power and precision of estimates of effectiveness (see forest plot below). When few or no studies are found this can help to pinpoint crucial areas and questions that need further research.

Manchester expertise

Members of the Institute of Population Health belong to the Evidence Synthesis Research Network which is jointly run my University of Manchester and NICE.

Two Cochrane review groups are based at Manchester:

Key publications

PDF slides

Download PDF slides of the presentation 'What is a Systematic Review?'