Cluster without fluster: The effect of correlated outcomes on inference in randomized clinical trials
Cluster without fluster: The effect of correlated outcomes on inference in randomized clinical trials
复制标题
DOI：
10.1002/sim.2977
复制
发表时间：
2008-03-15
影响因子：
2
通讯作者：
Follmann, Dean
中科院分区：
文献类型：
--
作者：
Proschan, Michael;Follmann, Dean
随机临床试验的推断通常基于零假设下结果独立且同分布的假设。在某些试验中，特别是在感染性疾病中，结果可能是相关的。这可能是事先知道的（例如，允许家庭成员的随机化）或完全无计划的（例如，随机化的参与者之间的性共享）。当相关性的形式基本上是不可知的时候，我们就特别担心，在这种情况下，我们就不能利用相关性来构造一个更有效的检验。相反，我们只能研究潜在相关性对独立样本检验统计量的影响。随机化倾向于平衡集群内的处理和对照分配，因此，所有可能的随机化分配的平均测试性能基本上不受任意相关性的影响是合乎逻辑的。我们证实了这种直觉表明，排列测试控制1型错误率在一定的平均意义上的聚类是独立的治疗分配。尽管如此，仍然有可能获得“坏”的随机化，使得集群的成员倾向于被分配到相同的治疗。在这种糟糕的随机化的条件下，I类错误率增加。出版社：John Wiley & Sons，Ltd.
Inference for randomized clinical trials is generally based on the assumption that outcomes are independently and identically distributed under the null hypothesis. In some trials, particularly in infectious disease, outcomes may be correlated. This may be known in advance (e.g. allowing randomization of family members) or completely unplanned (e.g. sexual sharing among randomized participants). There is particular concern when the form of the correlation is essentially unknowable, in which case we cannot take advantage of the correlation to construct a more efficient test. Instead, we can only investigate the impact of potential correlation on the independent-samples test statistic. Randomization tends to balance out treatment and control assignments within clusters, so it is logical that performance of tests averaged over all possible randomization assignments would be essentially unaffected by arbitrary correlation. We confirm this intuition by showing that a permutation test controls the type 1 error rate in a certain average sense whenever the clustering is independent of treatment assignment. It is nonetheless possible to obtain a 'bad' randomization such that members of a cluster tend to be assigned to the same treatment. Conditioned on such a bad randomization, the type I error rate is increased. Published in 2007 by John Wiley & Sons, Ltd.