Higher-moment approaches to approximate interval estimation for a certain intraclass correlation coefficient.
We consider the problem of constructing a confidence interval for the intraclass correlation coefficient in an interrater reliability study when the raters are assumed to be randomly selected from a population of raters. A Monte Carlo simulation study is conducted to investigate the true coverage probabilities of the commonly used intervals proposed by Fleiss and Shrout, which rely on Satterthwaite's two-moment approximation. These intervals are shown to be substantially anticonservative in certain cases. We propose intervals based on higher-moment approximations obtained using the Pearson system of distributions. The modified intervals are more conservative and generally more satisfactory than those obtained by the two-moment approximation. The competing methods are illustrated using data from a study of the natural history of facioscapulohumeral muscular dystrophy.
Zou
K H
KH
Department of Health Care Policy, Harvard Medical School, Boston, Massachusetts 02115, USA. zou@hcp.med.harvard.edu
McDermott
M P
MP
D003198:Computer Simulation; D016001:Confidence Intervals; D006801:Humans; D009010:Monte Carlo Method; D009119:Muscle Contraction / Q000502:physiology; D009136:Muscular Dystrophies / Q000503:physiopathology; D015588:Observer Variation; D018709:Statistics, Nonparametric