Education and debate

Meta-analysis: Potentials and promise

^a Department of Social Medicine, University of Bristol, Bristol BS8 2PR

Correspondence to: Dr Matthias Egger m.egger@bristol.ac.uk

	Introduction

The number of papers published on meta-analyses in medical research has increased sharply in the past 10 years (fig 1). The merits and perils of the somewhat mysterious procedure of meta-analysis, however, continue to be debated in the medical community.^{1 2 3} What, then, is meta-analysis? A useful definition was given by Huque: "A statistical analysis that combines or integrates the results of several independent clinical trials considered by the analyst to be 'combinable.'" ⁴ The terminology, however, is still debated, and expressions used concurrently include "overview," "pooling," and "quantitative synthesis." We believe that the term meta-analysis should be used to describe the statistical integration of separate studies, whereas "systematic review" is most appropriate for denoting any review of a body of data that uses clearly defined methods and criteria (box). Systematic reviews can include meta-analyses, . . . [Full text of this article]

What's in a name? The case for "meta-analysis"

	Historical notes

Summary points

	The unacceptable face of "statisticism"?

	Narrative reviews

	Limitations of a single study

	Epidemiology of results

	A more transparent appraisal

	Cumulative meta-analysis

	Acknowledgements

	References

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