固定样本的设计和完全序贯设计是临床试验的两种截然不同的方法:前者的样本大小在试验开始时即已确定,或固定不变;后者的样本大小取决于试验积累的结果,一旦处理达到显著性水平即停止试验。群组序贯设计介于两者之间,在定期举行(如每年一次)的研究工作会议中进行统计分析,最高允许分析次数应事先规定。在每次分析时应 The design of a fixed sample and complete sequential design are two distinct approaches to clinical trials: the sample size of the former is determined at the beginning of the trial, or it is fixed; the latter’s sample size depends on the results of trial accumulation. The treatment reaches the level of significance to stop the test. The sequential design of the group is somewhere in between, and statistical analysis is conducted in a research meeting that is held regularly (such as once a year). The maximum allowable number of analyses should be specified in advance. In each analysis should