While it is important to be able to read and interpret individual papers, as we have noted previously the results of a single study are never going to provide the complete answer to a question. To move towards this we need to review the literature more widely. There can be a number of reasons for doing this, some of which require a more comprehensive approach than others. If the aim is simply to increase our personal understanding of a new area then a few papers might provide adequate background material. Traditional narrative reviews, which give less emphasis to complete coverage of the literature and tend to be more qualitative, have value for exploring areas of uncertainty or novelty, but it is harder to scrutinise them for flaws. In contrast, a major decision regarding policy or practice should be based on a systematic review and perhaps a meta-analysis of all the relevant literature and it is this systematic approach that we will focus on here.
What is a systematic review?
A systematic review should be a helpful synthesis of all of the relevant data – highlighting patterns but not hiding differences. Although its primary data units are whole studies rather than individuals, it should still have a clearly formulated research question and be conducted with the same rigour as its component studies. So how should we go about conducting a systematic review? This is a major undertaking and excellent guidelines are widely available for would-be reviewers (see e.g. the Cochrane Collaboration website www.cochrane.org) so we will not attempt to cover all of the issues here. But, in brief, it involves:
• identifying all potentially relevant primary research studies that address the question of interest and including or excluding them according to predetermined criteria;
• abstracting the data in a standard format and critically appraising the included studies;
• summarising the findings of the studies, this might include a formal meta-analysis to combine the results of all of the studies into a single summary estimate; and
• an overall evaluation of the evidence with appropriate conclusions.
Review the options below to login to check your access.
Log in with your Cambridge Aspire website account to check access.
There are no purchase options available for this title.
If you believe you should have access to this content, please contact your institutional librarian or consult our FAQ page for further information about accessing our content.