DeMets D L, Gail M H
Biometrics. 1985 Dec;41(4):1039-44.
This paper presents simulations to determine the operating characteristics of several group sequential boundaries when applied to the repeated analysis of survival data at equal intervals of calendar time. Because the group sequential boundaries of Pocock (1977, Biometrika 64, 191-199) and O'Brien and Fleming (1979, Biometrics 35, 549-556) were constructed on the assumption that each interim analysis provides an equal increment of statistical information, these boundaries are not theoretically appropriate for interim analysis at prescheduled calendar times. Nonetheless, our simulations show that these boundaries yield size and power near nominal levels for repeated logrank analyses at equal intervals of calendar time.
本文展示了一些模拟，以确定在按日历时间等间隔对生存数据进行重复分析时，几种成组序贯界值的操作特征。由于Pocock（1977年，《生物统计学》64卷，191 - 199页）和成组序贯界值以及O'Brien和Fleming（1979年，《生物计量学》35卷，549 - 556页）是在每次中期分析提供同等统计信息增量的假设下构建的，所以这些界值在理论上并不适用于按预定日历时间进行的中期分析。尽管如此，我们的模拟表明，对于按日历时间等间隔进行的重复对数秩分析，这些界值产生的检验水准和检验效能接近名义水平。
