Greene Tom
Division of Epidemiology, Internal Medicine, School of Medicine, University of Utah, Williams Building, 295 Chipeta Way, Salt Lake City, UT, 84108, USA,
Methods Mol Biol. 2015;1281:225-47. doi: 10.1007/978-1-4939-2428-8_13.
Performing well-powered randomized controlled trials is of fundamental importance in clinical research. The goal of sample size calculations is to assure that statistical power is acceptable while maintaining a small probability of a type I error. This chapter overviews the fundamentals of sample size calculation for standard types of outcomes for two-group studies. It considers (1) the problems of determining the size of the treatment effect that the studies will be designed to detect, (2) the modifications to sample size calculations to account for loss to follow-up and nonadherence, (3) the options when initial calculations indicate that the feasible sample size is insufficient to provide adequate power, and (4) the implication of using multiple primary endpoints. Sample size estimates for longitudinal cohort studies must take account of confounding by baseline factors.
开展具有足够检验效能的随机对照试验在临床研究中至关重要。样本量计算的目的是确保统计检验效能可接受，同时保持I类错误的概率较小。本章概述了两组研究标准类型结局的样本量计算基础。它考虑了以下几个方面：（1）确定研究旨在检测的治疗效果大小的问题；（2）为考虑失访和不依从对样本量计算进行的调整；（3）当初始计算表明可行的样本量不足以提供足够的检验效能时的选择；（4）使用多个主要终点的影响。纵向队列研究的样本量估计必须考虑基线因素的混杂作用。
