Wassmer G
Institut für Medizinische Statistik, Informatik und Epidemiologie, Universität zu Köln, Germany.
Biometrics. 1998 Jun;54(2):696-705.
Recently, two methods for planning and conducting two-stage procedures were proposed (Bauer and Köhne, 1994, Biometrics 50, 1029-1041; Proschan and Hunsberger, 1995, Biometrics 51, 1315-1324). Both procedures allow the termination of the trial with the early acceptance of H0 in the absence of a treatment effect after performing the first stage of the study. Furthermore, the observed treatment effect at stage I can be used for planning and redesigning the second stage of the study in a way that protects the Type I error rate. The exact Type I error rate of the Proschan and Hunsberger approach is derived. It is shown that the two methods lead to similar decision rules with negligibly small differences in power and expected sample size. In terms of providing design tools and practical applicability, however, they differ. The practical performance of the procedures is discussed and recommendations for their use are given.
最近，有人提出了两种用于规划和实施两阶段程序的方法（鲍尔和克内，1994年，《生物统计学》第50卷，第1029 - 1041页；普罗尚和洪斯伯格，1995年，《生物统计学》第51卷，第1315 - 1324页）。这两种程序都允许在完成研究的第一阶段后，在没有治疗效果的情况下提前接受H0从而终止试验。此外，第一阶段观察到的治疗效果可用于规划和重新设计研究的第二阶段，以保护第一类错误率。推导了普罗尚和洪斯伯格方法的确切第一类错误率。结果表明，这两种方法导致了相似的决策规则，在功效和预期样本量方面的差异小到可以忽略不计。然而，在提供设计工具和实际适用性方面，它们有所不同。讨论了这些程序的实际性能并给出了使用建议。
