Tan M, Xiong X, Kutner M H
Department of Biostatistics and Epidemiology, Cleveland Clinic Foundation, Ohio 44195-5196, USA.
Biometrics. 1998 Jun;54(2):682-95.
We propose a group sequential method based on the sequential conditional probability ratio test and show that it has the conservatism desired in practice. We also propose calculating the discordant probability, that is, the probability that the sequential test concludes differently from a fixed-sample test at the planned end of the trial, recognizing that this probability could be substantial, even if the sequential test has the same size and power as the fixed-sample size test at the planned end of the study. In addition, we show that the proposed method can be used as a stochastic curtailing tool. Thus, the method accommodates unplanned interim analyses as well as those deemed necessary based on data trends, virtually without inflating the type I error, but it is less conservative than the usual stochastic curtailing. The method is implemented through an interactive computer program.
我们提出了一种基于序贯条件概率比检验的序贯方法，并表明它具有实际所需的保守性。我们还建议计算不一致概率，即在试验计划结束时序贯检验得出的结论与固定样本检验不同的概率，认识到即使序贯检验在研究计划结束时与固定样本量检验具有相同的规模和功效，该概率也可能很大。此外，我们表明所提出的方法可以用作随机截尾工具。因此，该方法既适用于计划外的期中分析，也适用于基于数据趋势认为有必要进行的期中分析，几乎不会增加I型错误，但比通常的随机截尾保守性更低。该方法通过交互式计算机程序实现。
