A basic introduction to fixed-effect and random-effects models for meta-analysis
Article first published online: 21 NOV 2010
Copyright © 2010 John Wiley & Sons, Ltd.
Research Synthesis Methods
Volume 1, Issue 2, pages 97–111, April/June 2010
How to Cite
Borenstein, M., Hedges, L. V., Higgins, J. P.T. and Rothstein, H. R. (2010), A basic introduction to fixed-effect and random-effects models for meta-analysis. Res. Synth. Method, 1: 97–111. doi: 10.1002/jrsm.12
- Issue published online: 25 NOV 2010
- Article first published online: 21 NOV 2010
- Manuscript Accepted: 25 AUG 2010
- Manuscript Revised: 19 AUG 2010
- Manuscript Received: 1 DEC 2009
- statistical models;
- research synthesis;
- systematic reviews
There are two popular statistical models for meta-analysis, the fixed-effect model and the random-effects model. The fact that these two models employ similar sets of formulas to compute statistics, and sometimes yield similar estimates for the various parameters, may lead people to believe that the models are interchangeable. In fact, though, the models represent fundamentally different assumptions about the data. The selection of the appropriate model is important to ensure that the various statistics are estimated correctly. Additionally, and more fundamentally, the model serves to place the analysis in context. It provides a framework for the goals of the analysis as well as for the interpretation of the statistics.
In this paper we explain the key assumptions of each model, and then outline the differences between the models. We conclude with a discussion of factors to consider when choosing between the two models. Copyright © 2010 John Wiley & Sons, Ltd.