Grayling Michael J, Wason James M S, Mander Adrian P
MRC Biostatistics Unit, Hub for Trials Methodology Research, Cambridge, UK.
Institute of Health & Society, Newcastle University, Newcastle, UK.
Commun Stat Theory Methods. 2021;50(1):18-34. doi: 10.1080/03610926.2019.1628273. Epub 2019 Jun 17.
We describe and compare two methods for the group sequential design of two-arm experiments with Poisson distributed data, which are based on a normal approximation and exact calculations respectively. A framework to determine near-optimal stopping boundaries is also presented. Using this framework, for a considered example, we demonstrate that a group sequential design could reduce the expected sample size under the null hypothesis by as much as 44% compared to a fixed sample approach. We conclude with a discussion of the advantages and disadvantages of the two presented procedures.
我们描述并比较了两种用于双臂实验的成组序贯设计方法，该实验的数据服从泊松分布，这两种方法分别基于正态近似和精确计算。我们还提出了一个确定近似最优停止边界的框架。使用这个框架，对于一个考虑的示例，我们证明与固定样本方法相比，成组序贯设计在原假设下可以将预期样本量减少多达44%。我们最后讨论了所提出的两种方法的优缺点。
