文章基本信息

标题：Allocation techniques for balance at baseline in cluster randomized trials: a methodological review
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作者：Noah M Ivers ; Ilana J Halperin ; Jan Barnsley 等
期刊名称：Trials
印刷版ISSN：1745-6215
电子版ISSN：1745-6215
出版年度：2012
卷号：13
期号：1
页码：120
DOI：10.1186/1745-6215-13-120
语种：English
出版社：BioMed Central
摘要：Reviews have repeatedly noted important methodological issues in the conduct and reporting of cluster randomized controlled trials (C-RCTs). These reviews usually focus on whether the intracluster correlation was explicitly considered in the design and analysis of the C-RCT. However, another important aspect requiring special attention in C-RCTs is the risk for imbalance of covariates at baseline. Imbalance of important covariates at baseline decreases statistical power and precision of the results. Imbalance also reduces face validity and credibility of the trial results. The risk of imbalance is elevated in C-RCTs compared to trials randomizing individuals because of the difficulties in recruiting clusters and the nested nature of correlated patient-level data. A variety of restricted randomization methods have been proposed as way to minimize risk of imbalance. However, there is little guidance regarding how to best restrict randomization for any given C-RCT. The advantages and limitations of different allocation techniques, including stratification, matching, minimization, and covariate-constrained randomization are reviewed as they pertain to C-RCTs to provide investigators with guidance for choosing the best allocation technique for their trial.
关键词：Cluster-randomized trials ; Balanced allocation ; Restricted randomization