Medical and Pharmaceutical Statistics Research Unit, Department of Mathematics and Statistics, Lancaster University, UK.
Stat Methods Med Res. 2011 Dec;20(6):635-56. doi: 10.1177/0962280210379036. Epub 2010 Sep 27.
The methodology of group sequential trials is now well established and widely implemented. The benefits of the group sequential approach are generally acknowledged, and its use, when applied properly, is accepted by researchers and regulators. This article describes how a wide range of group sequential designs can easily be implemented using two accessible SAS functions. One of these, PROBBNRM is a standard function, while the other, SEQ, is part of the interactive matrix language of SAS, PROC IML. The account focuses on the essentials of the approach and reveals how straightforward it can be. The design of studies is described, including their evaluation in terms of the distribution of final sample size. The conduct of the interim analyses is discussed, with emphasis on the consequences of inevitable departures from the planned schedule of information accrual. The computations required for the final analysis, allowing for the sequential design, are closely related to those conducted at the design stage. Illustrative examples are given and listings of suitable of SAS code are provided.
群组序贯试验方法现在已经得到很好的确立和广泛的应用。群组序贯方法的好处被普遍认可，并且当其被正确应用时，它被研究人员和监管机构所接受。本文描述了如何使用两个易于访问的 SAS 函数轻松实现各种群组序贯设计。其中之一，PROBBNRM 是一个标准函数，而另一个，SEQ，是 SAS 的交互式矩阵语言 PROC IML 的一部分。该说明重点介绍了该方法的要点，并揭示了其简单性。描述了研究的设计，包括根据最终样本量分布对其进行评估。讨论了中期分析的进行，重点是不可避免地偏离计划信息累积进度表的后果。最终分析所需的计算，允许进行序贯设计，与设计阶段进行的计算密切相关。提供了说明性示例和适合的 SAS 代码清单。
