Figure 1.

Left panel: the coverage probabilities of the proposed refined (solid points) and conventional (hollow points) methods for the first outcome, where the nominal coverage is 95% and where the between-study covariance matrix has been estimated using the method of moments. Right panel: the ratio of the average lengths of nominal 95% confidence intervals using the refined and conventional procedures, where ratios greater than one indicate that the refined method provides greater average confidence interval lengths. A total of 100 000 simulations were used for each simulation run.