A rank-sum test for clustered data when the number of subjects in a group within a cluster is informative.
A rank-sum test for clustered data when the number of subjects in a group within a cluster is informative.
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DOI：
10.1111/biom.12447
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发表时间：
2016-06
期刊：
影响因子：
1.9
通讯作者：
Datta S
中科院分区：
文献类型：
--
作者：
Dutta S;Datta S
Wilcoxon秩和检验是一种流行的非参数检验，用于比较两个独立的人群（组）。近年来，在扩展用于聚类数据的Wilcoxon秩和检验方面有新的尝试，其中之一（Journal of the American Statistical Association 100，908-915）解决了信息聚类大小的问题，即，当结果和集群规模相关时。我们面临的情况是，集群中特定于组的边缘分布取决于该组中的观测数量（即，簇内组大小）。我们开发了一种新的扩展的秩和检验处理这种情况。我们比较了我们的测试与Datta-Satten测试，以及天真Wilcoxon秩和检验的性能。使用一个自然发生的模拟模型的信息集群内组的大小，我们表明，只有我们的测试保持正确的大小。我们还将我们的测试与经典的符号秩检验进行了比较，该检验基于每个组中由聚类成员配对的结果值的平均值。虽然这个测试保持了大小，但它的功耗比我们的测试低。扩展到多组比较和集群的情况下，没有从所有组的样本进行了讨论。我们应用我们的测试来确定牙周患者的上牙和下牙之间以及近中牙和颊侧之间的附着丧失是否存在差异。
The Wilcoxon rank-sum test is a popular nonparametric test for comparing two independent populations (groups). In recent years, there have been renewed attempts in extending the Wilcoxon rank sum test for clustered data, one of which (, Journal of the American Statistical Association 100, 908–915) addresses the issue of informative cluster size, i.e., when the outcomes and the cluster size are correlated. We are faced with a situation where the group specific marginal distribution in a cluster depends on the number of observations in that group (i.e., the intra-cluster group size). We develop a novel extension of the rank-sum test for handling this situation. We compare the performance of our test with the Datta-Satten test, as well as the naive Wilcoxon rank sum test. Using a naturally occurring simulation model of informative intra-cluster group size, we show that only our test maintains the correct size. We also compare our test with a classical signed rank test based on averages of the outcome values in each group paired by the cluster membership. While this test maintains the size, it has lower power than our test. Extensions to multiple group comparisons and the case of clusters not having samples from all groups are also discussed. We apply our test to determine whether there are differences in the attachment loss between the upper and lower teeth and between mesial and buccal sites of periodontal patients.