Different estimation methods for covariance parameters in meta-analyses can result in conflicting p-values concerning the test of treatment effect. We propose a valid method to overcome this problem at least partially by introducing a new estimator for the standard deviation of the common...

A class of self-designing clinical trials is considered which according to an effective but simple, finite learning algorithm consists of automatically adaptively planned weighted group sequential trials with a decision about rejection of the null-hypothesis at each step, but the full...