Intraclass Correlation Coefficients Typical of Cluster-Randomized Studies: Estimates From the Robert Wood Johnson Prescription for Health Projects
Intraclass Correlation Coefficients Typical of Cluster-Randomized Studies: Estimates From the Robert Wood Johnson Prescription for Health Projects
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DOI：
10.1370/afm.1347
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发表时间：
2012-05-01
影响因子：
4.4
通讯作者：
Mold, James W.
中科院分区：
文献类型：
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作者：
Thompson, David A.;Fernald, Douglas H.;Mold, James W.
目的进行整群随机研究的研究人员在制定研究计划时必须考虑到整群，否则可能导致研究力量不足。为了进行充分的计划，研究人员需要以组内相关系数(ICCs)的形式准确地估计分组。方法我们使用了来自8个基于实践的研究网络的61个实践的5042名患者的数据，这些数据来自罗伯特·伍德·约翰逊基金会赞助的健康处方计划，以估计人口统计学和行为变量以及医生和实践特征的ICCs。结果计算了年龄(ICC=0.151)、种族(ICC=0.265)、吸烟(ICC=0.118)和不健康饮食(ICC=0.206)等行为的ICC。患者与吸烟、饮食或锻炼相关的意图改变行为的聚集性较小(ICC
PURPOSE Researchers who conduct cluster-randomized studies must account for clustering during study planning; failure to do so can result in insufficient study power. To plan adequately, investigators need accurate estimates of clustering in the form of intraclass correlation coefficients (ICCs).METHODS We used data for 5,042 patients, from 61 practices in 8 practice-based research networks, obtained from the Prescription for Health program, sponsored by the Robert Wood Johnson Fund, to estimate ICCs for demographic and behavioral variables and for physician and practice characteristics. We used an approach similar to analysis of variance to calculate ICCs for binary variables and mixed models that directly estimated between- and within-cluster variances to calculate ICCs for continuous variables.RESULTS ICCs indicating substantial within-practice clustering were calculated for age (ICC = 0.151), race (ICC = 0.265), and such behaviors as smoking (ICC = 0.118) and unhealthy diet (ICC = 0.206). Patients' intent-to-change behaviors related to smoking, diet, or exercise were less clustered (ICCs