DerSimonian-Laird and Hartung-Knapp-Sidik-Jonkman error rates for continuous outcomes, for various I
and mixtures of trial sizes. Legend: A: Equally sized trials; B: One small trial, 1/10th of other trials; C: 50–50 small and large trials (ratio 1:10); D: one large trial (10 times larger than other trials). Vertical bars refer to the minimum and maximum error rates over the group sizes. The lines connect the means of these error rates. DL: DerSimonian-Laird meta-analysis method. HKSJ: Hartung-Knapp-Sidik-Jonkman meta-analysis method.