Meta-analysis

Meta-analysis is a quantitative method of combining the results of previous separate but related studies to synthesise summaries and conclusions. It serves to introduce cross-study precision in many fields of research, and it is most useful when individual studies are too small to yield valid conclusions.

In its most general form, meta-analysis uses a set of quantitative techniques that permit synthesising results of many types of research, including opinion surveys, correlation studies, experimental and quasi-experimental studies, and regression analyses probing causal models. The researcher gathers together all the studies relevant to a given issue and then constructs at least one indicator of the relationships under investigation from each study. Study-level data can thus be analysed like any other data.

By combining as much of the existing evidence as possible on a specific topic into a common framework, meta-analysis is extremely useful in supporting and improving policy decision making, and it is widely used in several disciplines for just that purpose.