# A re-evaluation of fixed effect(s) meta-analysis

Published on Jan 1, 2018in Journal of The Royal Statistical Society Series A-statistics in Society2.483

· DOI :10.1111/RSSA.12275

Abstract

Metaâ€ analysis is a common tool for synthesizing results of multiple studies. Among methods for performing metaâ€ analysis, the approach known as â€˜fixed effectsâ€™ or â€˜inverse variance weightingâ€™ is popular and widely used. A common interpretation of this method is that it assumes that the underlying effects in contributing studies are identical, and for this reason it is sometimes dismissed by practitioners. However, other interpretations of fixed effects analyses do not make this assumption, yet appear to be little known in the literature. We review these alternative interpretations, describing both their strengths and their limitations. We also describe how heterogeneity of the underlying effects can be addressed, with the same minimal assumptions, through either testing or metaâ€ regression. Recommendations for the practice of metaâ€ analysis are given; it is hoped that these will foster more direct connection of the questions that metaâ€ analysts wish to answer with the statistical methods they choose.

Figures & Tables