Robust R-Estimation of a Consensus Value from Multi-Center Studies |
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Authors: | Inkyung Jung Pranab Kumar Sen |
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Institution: | 1. Department of Ambulatory Care and Prevention , Harvard Medical School and Harvard Pilgrim Health Care , Boston , Massachusetts , USA inkyung_jung@harvardpilgrim.org;3. Departments of Biostatistics, and Statistics and Operations Research , University of North Carolina , Chapel Hill , North Carolina , USA |
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Abstract: | We consider multi-center experiments (for determining a consensus value) conducted in possibly heterogeneous set-ups leading to unbalanced heteroscedastic one-way random effects models. When normality of both the random components and their homoscedasticity are in doubt, standard statistical methods may not be valid. Two robust R-estimators (for the common location parameter), based on signed-rank statistics, are proposed and their properties studied. When large heteroscedasticity is present or the distribution of random effect is abnormal, the proposed estimators perform better than the classical weighted least squares and selected estimators. This feature is illustrated with an arsenic in oyster tissue problem, along with some other simulation studies. |
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Keywords: | Heteroscedasticity One-way random effects model R-estimator Wilcoxon signed-rank statistic |
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