@article{d1ed7694e8a14a92896adf14bcc1c75f,
title = "Robust multivariate nonparametric tests for detection of two-sample location shift in clinical trials",
abstract = "This article presents and investigates performance of a series of robust multivariate nonparametric tests for detection of location shift between two multivariate samples in randomized controlled trials. The tests are built upon robust estimators of distribution locations (medians, Hodges-Lehmann estimators, and an extended U statistic) with both unscaled and scaled versions. The nonparametric tests are robust to outliers and do not assume that the two samples are drawn from multivariate normal distributions. Bootstrap and permutation approaches are introduced for determining the p-values of the proposed test statistics. Simulation studies are conducted and numerical results are reported to examine performance of the proposed statistical tests. The numerical results demonstrate that the robust multivariate nonparametric tests constructed from the Hodges-Lehmann estimators are more efficient than those based on medians and the extended U statistic. The permutation approach can provide a more stringent control of Type I error and is generally more powerful than the bootstrap procedure. The proposed robust nonparametric tests are applied to detect multivariate distributional difference between the intervention and control groups in the Thai Healthy Choices study and examine the intervention effect of a four-session motivational interviewing-based intervention developed in the study to reduce risk behaviors among youth living with HIV.",
author = "Xuejun Jiang and Xu Guo and Ning Zhang and Bo Wang and Bo Zhang",
note = "Funding Information: Dr. Xuejun Jiang{\textquoteright}s research was partially supported by Natural Science Foundation of China (11101432), Natural Science Foundation of Guangdong Province of China (2017A030313012), and Shenzhen Sci-Tech Fund (JCYJ20170307110329106). Dr. Xu Guo{\textquoteright}s research was partially supported by National Natural Science Foundation of China (11601227 and 11626130) and Natural Science Foundation of Jiangsu Province, China (BK20150732). The research project was partially funded by the National Institute of Mental Health (R34MH077523). The authors are thankful to the Academic Editor and the two anonymous referees for their valuable comments and suggestions, which have improved the article substantially. Dr. Xuejun Jiang{\textquoteright}s research was partially supported by Natural Science Foundation of China (11101432), Natural Science Foundation of Guangdong Province of China (2017A030313012), and Shenzhen Sci-Tech Fund (JCYJ20170307110329106). Dr. Xu Guo{\textquoteright}s research was partially supported by National Natural Science Foundation of China (11601227 and 11626130 and Natural Science Foundation of Jiangsu Province, China (BK20150732). The research project was partially funded by the National Institute of Mental Health (R34MH077523). The authors thank the principal investigator of the project, Dr. Chokechai Rongkavilit at Valley Children{\textquoteright}s Hospital for generously providing data for statistical analysis. Publisher Copyright: {\textcopyright} 2018 Jiang et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.",
year = "2018",
month = apr,
doi = "10.1371/journal.pone.0195894",
language = "English (US)",
volume = "13",
journal = "PloS one",
issn = "1932-6203",
publisher = "Public Library of Science",
number = "4",
}