Balance in cluster randomized trials
Balance in cluster randomized trials
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DOI：
10.1002/1097-0258(20010215)20:3
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发表时间：
2001-02-15
影响因子：
2
通讯作者：
Butcher, I
中科院分区：
文献类型：
--
作者：
Raab, GM;Butcher, I
本文探讨了在整群随机试验设计中平衡治疗组间协变量的作用。一般表达式获得两个标准，以评估设计的平行组研究，两种治疗。第一个是估计治疗效应的方差，第二个是通过调整协变量估计治疗效应的变化程度。有人认为，这些第二个是更重要的集群随机试验。提出了从研究开始时可用的协变量获得平衡设计的方法。不平衡测量用于比较设计平衡试验组间重要协变量的程度。选择良好平衡设计的几种方法是可能的。从具有可接受偏倚的设计类中随机选择一个成员的方法将允许随机化推断以及基于模型的推断。这些方法说明了从一个试验的学校为基础的性教育的数据。版权所有（C）2001约翰威利父子有限公司
This paper explores the role of balancing covariates between treatment groups in the design of cluster randomized trials. General expressions are obtained for two criteria to evaluate designs for parallel group studies with two treatments. The first is the variance of the estimated treatment effect and the second is the extent to which the estimated treatment effect is changed by adjusting for covariates. It is argued that the second of these is more important for cluster randomized trials. Methods of obtaining balanced designs from covariates which are available at the start of a study are proposed. An imbalance measure is used to compare the extent to which designs balance important covariates between the arms of a trial. Several approaches to selecting a well balanced design are possible. A method that randomly selects one member from the class of designs with acceptable bias will allow randomization inference as well as model-based inference. The methods are illustrated with data from a trial of school-based sex education. Copyright (C) 2001 John Wiley & Sons, Ltd.