Simple moment-based inferences of generalized concordance correlation |
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Authors: | John J Chen Guangxiang Zhang Chen Ji George F Steinhardt |
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Institution: | 1. Department of Preventive Medicine , State University of New York at Stony Brook , Stony Brook, NY, 11794-8036, USA;2. Department of Urology , Wayne State University School of Medicine , Detroit, MI, 48201, USA |
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Abstract: | We proposed two simple moment-based procedures, one with (GCCC1) and one without (GCCC2) normality assumptions, to generalize the inference of concordance correlation coefficient for the evaluation of agreement among multiple observers for measurements on a continuous scale. A modified Fisher's Z-transformation was adapted to further improve the inference. We compared the proposed methods with U-statistic-based inference approach. Simulation analysis showed desirable statistical properties of the simplified approach GCCC1, in terms of coverage probabilities and coverage balance, especially for small samples. GCCC2, which is distribution-free, behaved comparably with the U-statistic-based procedure, but had a more intuitive and explicit variance estimator. The utility of these approaches were illustrated using two clinical data examples. |
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Keywords: | generalized concordance correlation coefficient interobserver agreement modified Fisher's Z-transformation reliability |
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