Norman G R
McMaster University, Hamilton, Ontario, Canada.
J Clin Epidemiol. 1989;42(11):1097-105. doi: 10.1016/0895-4356(89)90051-6.
The literature on the measurement of change is often confusing and contradictory. Some authors advocate the use of change scores as the best approach to the analysis of treatment effects in clinical trials; others maintain that change scores should be avoided entirely. This paper reviews these arguments and demonstrates that contradictions arise in part from different definitions of change, and in part from some misunderstanding of the relationship between reliability and responsiveness to change. Conditions under which it is, and is not appropriate to use change scores in experimental designs are specified, and formulae for sample size calculations are introduced.
关于变化测量的文献往往令人困惑且相互矛盾。一些作者主张使用变化分数作为临床试验中分析治疗效果的最佳方法；另一些人则坚持应完全避免使用变化分数。本文回顾了这些论点，并表明矛盾部分源于对变化的不同定义，部分源于对可靠性与变化反应性之间关系的一些误解。明确了在实验设计中使用变化分数合适和不合适的条件，并介绍了样本量计算的公式。
