Comparison of intraclass correlation coefficient estimates and standard errors between using cross-sectional and repeated measurement data: the Safety Check cluster randomized trial.
Comparison of intraclass correlation coefficient estimates and standard errors between using cross-sectional and repeated measurement data: the Safety Check cluster randomized trial.
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DOI：
10.1016/j.cct.2010.11.001
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发表时间：
2011-03
影响因子：
2.2
通讯作者：
Barkin S
中科院分区：
文献类型：
--
作者：
Ip EH;Wasserman R;Barkin S
在临床研究中设计聚类随机试验通常需要准确估计类内相关性，这可以量化聚类内单位（如参与者）之间的相关性强度，如实践。已公布的国际商会估计，即使有，也经常存在置信区间过宽的问题。使用一项关于儿童暴力预防的全国性、随机、对照研究——安全检查——的数据，我们比较了仅使用基线数据和同时使用基线和随访数据两种方法得出的ICC值。后一种方法使用方差成分分解方法，可以灵活地处理复杂的数据集。例如，它允许结果变量随时间的变化和不平衡集群设计。此外，我们使用自举法评估ICC估计和标准误差的大样本公式。我们的研究结果表明，在实践中，提供者的ICC估计值范围为0.012至0.11，在提供者的家庭中，ICC估计值范围为0.018至0.11。只使用基线和重复测量方法得出的估计值非常一致，除非重复测量的差异很大。在实践和提供者水平上，仅使用基线重复测量，ICC置信限宽度的减少分别为62%和42%。因此，本文的贡献包括两个要素，即提高ICC准确性的方法，以及为儿科和其他对设计与当前研究相似的聚类随机试验感兴趣的研究人员报告此类数量。
Designing cluster randomized trials in clinical studies often requires accurate estimates of intraclass correlation, which quantifies the strength of correlation between units, such as participants, within a cluster, such as a practice. Published ICC estimates, even when available, often suffer from the problem of wide confidence intervals. Using data from a national, randomized, controlled study concerning violence prevention for children—the Safety Check—we compare the ICC values derived from two approaches only baseline data and using both baseline and follow-up data. Using a variance component decomposition approach, the latter method allows flexibility in handling complex data sets. For example, it allows for shifts in the outcome variable over time and for an unbalanced cluster design. Furthermore, we evaluate the large-sample formula for ICC estimates and standard errors using the bootstrap method. Our findings suggest that ICC estimates range from 0.012 to 0.11 for providers within practice and range from 0.018 to 0.11 for families within provider. The estimates derived from the baseline-only and repeated-measurements approaches agree quite well except in cases in which variation over repeated measurements is large. The reductions in the widths of ICC confidence limits from using repeated measurement over baseline only are, respectively, 62% and 42% at the practice and provider levels. The contribution of this paper therefore includes two elements, which are a methodology for improving the accuracy of ICC, and the reporting of such quantities for pediatric and other researchers who are interested in designing clustered randomized trials similar to the current study.
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影响因子：
5.4
作者：
HANNAN, PJ;MURRAY, DM;MCGOVERN, PG
通讯作者：
MCGOVERN, PG
影响因子：
7.2
作者：
Adams, G;Gulliford, MC;Campbell, MJ
通讯作者：
Campbell, MJ
影响因子：
2
作者：
Eldridge, Sandra M.;Ukoumunne, Obioha C.;Carlin, John B.
通讯作者：
Carlin, John B.
影响因子：
2.2
作者：
Murray, DM;Van Horn, ML;Arthur, MW
通讯作者：
Arthur, MW
影响因子：
7.2
作者：
Gulliford, MC;Adams, G;Campbell, MJ
通讯作者：
Campbell, MJ