Statistical power and optimal design for multisite randomized trials
Statistical power and optimal design for multisite randomized trials
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DOI：
10.1037//1082-989x.5.2.199
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发表时间：
2000-06-01
影响因子：
7
通讯作者：
Liu, XF
中科院分区：
文献类型：
--
作者：
Raudenbush, SW;Liu, XF
多地点试验广泛应用于心理健康研究和教育，使实验者能够评估不同地点治疗的平均影响，不同地点治疗影响的差异，以及地点特征对治疗效果的调节作用。关键的设计决策包括每个研究中心的样本量和研究中心的数量。为了考虑功效影响，本文提出了一个标准化分层线性模型，并使用类似于J. Cohen（1988）提出的经验法则来处理小、中、大效应量以及小、中、大治疗-地点方差。还考虑了各地点内部和各地点之间资源的最佳分配，作为各级别差异组成部分和成本的函数。该方法推广到具有类似结构的准实验。这些想法都说明了新开发的软件。
The multisite trial, widely used in mental health research and education, enables experimenters to assess the average impact of a treatment across sites, the variance of treatment impact across sites, and the moderating effect of site characteristics on treatment efficacy. Key design decisions include the sample size per site and the number of sites. To consider power implications, this article proposes a standardized hierarchical linear model and uses rules of thumb similar to those proposed by J. Cohen (1988) for small, medium, and large effect sizes and for small, medium, and large treatment-by-site variance. Optimal allocation of resources within and between sites as a function of variance components and costs at each level are also considered. The approach generalizes to quasiexperiments with a similar structure. These ideas are illustrated with newly developed software.