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Table 2 Summary of the four meta-analysis examples

From: Confidence intervals for the between-study variance in random-effects meta-analysis using generalised heterogeneity statistics: should we use unequal tails?

Meta k I 2 Equal- α W-optimal \(\alpha ^{*}_{2}\) Width
Analysis    CI (τ) interval (τ)   Ratio
CERVIX3 5 56 % (0, 1.287) (0, 1.048) 0.050 0.814
NSCLC4 11 75 % (0.227, 0.887) (0.193, 0.824) 0.040 0.954
NSCLC1 17 45 % (0.013, 0.426) (0.028, 0.436) 0.021 0.986
CERVIX1 18 62 % (0.201, 0.707) (0.182, 0.678) 0.035 0.982
  1. I2 is the heterogeneity statistic of Higgins and Thompson [28]. In each case we show the equal tailed (α1=α2=0.025) 95 % confidence interval for τ, the W-optimal interval for τ, the value of \(\alpha ^{*}_{2}\) that provides the W-optimal interval (also for τ) and the ratio of the width of the W-optimal interval and the equal tailed confidence interval. In each case we see that there is reduction in the interval width by adopting α2>>α1