Fig. 1

Coverage probabilities of HKSJ and mKH 95 % confidence intervals. Probabilities are shown in dependence of the number k of studies and the amount of heterogeneity I ². The four different scenarios A–D correspond to different amounts of imbalance between the study-specific standard errors s _i . The DerSimonian-Laird (DL) method was used for estimation of the heterogeneity variance τ ²