The choice of sample size in the context of co-primary endpoints for a randomised trial is discussed. Current guidance can leave endpoints with unequal marginal power. A method is provided to achieve equal marginal power by using the flexibility provided in multiple testing procedures. A comparison is made to several choices of rule to determine the sample size, in terms of the study design and its operating characteristics.

翻译：本文讨论了随机化试验中共同主要终点情形下的样本量选择问题。现有指导原则可能导致各终点的边际功效不均衡。我们提出一种方法，利用多重检验程序提供的灵活性来实现等边际功效。从研究设计及其操作特征的角度，将本方法与多种样本量确定规则进行了比较。