Estimates of heterogeneity (I2) can be biased in small meta-analyses
Methodology
2017-03-24 v2
Abstract
In meta-analysis, the fraction of variance that is due to heterogeneity is known as I2. We show that the usual estimator of I2 is biased. The bias is largest when a meta-analysis has few studies and little heterogeneity. For example, with 7 studies and the true value of I2 at 0, the average estimate of I2 is .124. Estimates of I2 should be interpreted cautiously when the meta-analysis is small and the null hypothesis of homogeneity (I2=0) has not been rejected. In small meta-analyses, confidence intervals may be preferable to point estimates for I2.
Keywords
Cite
@article{arxiv.1410.2296,
title = {Estimates of heterogeneity (I2) can be biased in small meta-analyses},
author = {Paul T. von Hippel},
journal= {arXiv preprint arXiv:1410.2296},
year = {2017}
}
Comments
7 pages + 3 figures