Charlton B G
Department of Epidemiology and Public Health, University of Newcastle upon Tyne.
J R Coll Physicians Lond. 1995 Mar-Apr;29(2):96-100.
A recent development of the therapeutic trial has been the mega-trial: a large, simple randomised trial analysed on an 'intention to treat' basis. Mega-trials have advantages in terms of increased statistical power, but also raise several new questions of interpretation. In mega-trials, randomisation serves to achieve identical allocation groups in a situation where there is poor experimental control and a large measure of between-subject variation. The results of mega-trials cannot readily be generalised because their conclusions are observations, not casual hypotheses, and are therefore not testable. In this sense, mega-trials can be repeated but cannot be replicated. Basic science and clinical science both seek understanding at the level of the individual subject; but in a mega-trial, analysis is only meaningful at the group level. The non-scientific nature of mega-trials derives from their methodology, which dispenses with the scientific aim of maximum experimental control to remove or minimise bias, and instead uses randomisation to achieve an equal distribution of bias between groups.
一种基于“意向性治疗”原则进行分析的大型简单随机试验。大规模试验在提高统计效力方面具有优势，但也引发了一些新的解释问题。在大规模试验中，随机化用于在实验控制不佳且受试者间变异程度较大的情况下实现相同的分配组。大规模试验的结果难以轻易推广，因为其结论是观察结果，而非因果假设，因此无法进行检验。从这个意义上说，大规模试验可以重复，但无法复制。基础科学和临床科学都试图在个体层面上寻求理解；但在大规模试验中，分析仅在群体层面上才有意义。大规模试验的非科学性源于其方法，该方法摒弃了最大程度进行实验控制以消除或最小化偏差这一科学目标，而是使用随机化来使偏差在组间均匀分布。
