A homogeneity test in overviews with group sequentially monitored clinical trials.

It is known that using statistical stopping rules in clinical trials can create an artificial heterogeneity of treatment effects in overviews of related trials (Hughes, Freedman, and Pocock, 1992, Biometrics 48, 41-53). If the true treatment effect being tested is small, as is often the case, the homogeneity test by DerSimonian and Laird (1986, Controlled Clinical Trials 7, 177-188) violates the size of the test very severely. This paper provides a new homogeneity test, which preserves the size of the test more accurately. The operating characteristics of the new test are examined through simulations.