Estimation in meta‐analyses of mean difference and standardized mean difference

Methods for random‐effects meta‐analysis require an estimate of the between‐study variance, τ 2 . The performance of estimators of τ 2 (measured by bias and coverage) affects their usefulness in assessing heterogeneity of study‐level effects and also the performance of related estimators of the overall effect. However, as we show, the performance of the methods varies widely among effect measures. For the effect measures mean difference (MD) and...