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This Unit examines the principles of combining results from different studies to come up with some meaningful and generalisable conclusions. A systematic review synthesises or provides a summary of all the methodologically sound studies relating to a particular topic area. A Meta-analysis is the term used for a technique that statistically combines the results of quantitative studies to provide a more precise effect of the results. This is often done as part of a systematic review. Qualitative researchers prefer the approach of metasynthesis which combines the results of qualitative research to develop an overarching or more conclusive way of thinking about the topic in question (Cullum).

Often practitioners want some guidance on what to do, and the Unit also shows how guidelines may be produced, that indicate what should be done, and how strong the recommendations are for various stages of the process.

You may want to have access to a statistics textbook (or Web page explaining some definitions) to help you with some of the statistical terms used in this Unit.


Cullum N. et al. editors. Evidence based nursing: an introduction. Oxford: Blackwell Publishing Ltd; 2008.

Dunn C. Statistics: confidence and significance. Available from URL