The Intra-Cluster Correlation Coefficient in Cluster Randomized Trials: A Review of Definitions
The Intra-Cluster Correlation Coefficient in Cluster Randomized Trials: A Review of Definitions
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DOI：
10.1111/j.1751-5823.2009.00092.x
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发表时间：
2009-12-01
影响因子：
2
通讯作者：
Carlin, John B.
中科院分区：
文献类型：
--
作者：
Eldridge, Sandra M.;Ukoumunne, Obioha C.;Carlin, John B.
主要结局的群内相关系数（ICC）在整群随机试验（CRT）的设计和分析中起着关键作用，但该参数的精确定义有些难以捉摸，特别是在非正态分布结局的背景下。在本文中，我们提供了一个统一的处理ICC中使用的CRT。我们提出了一个一般的定义ICC，可以表示在不同的方式取决于用于描述数据的建模方法，说明如何将这个一般定义应用于连续和二分的结果。二分结果的复杂性更大;特别是，ICC的通常定义不能直接与二分结果常用的Logistic正态模型的参数相关。我们展示了协变量引入时ICC的定义是如何不同的。最后，我们使用我们的框架和定义的ICC绘制出那些解释和选择的ICC值时，规划CRT的影响。
P>The intra-cluster correlation coefficient (ICC) of the primary outcome plays a key role in the design and analysis of cluster randomized trials (CRTs), but the precise definition of this parameter is somewhat elusive, especially in the context of non-normally distributed outcomes. In this paper, we provide a unified treatment of ICC as used in CRTs. We present a general definition of the ICC that may be expressed in different ways depending on the modelling approach used to describe the data, illustrating how this general definition is applied to continuous and dichotomous outcomes. Greater complexity arises for dichotomous outcomes; in particular, the usual definition of the ICC cannot be related directly to the parameters of the logistic-normal model that is commonly used for dichotomous outcomes. We show how the definition of the ICC is different when covariates are introduced. Finally, we use our framework and definition of the ICC to draw out implications for those interpreting and choosing values of the ICC when planning CRTs.