title: Confidence interval construction for a difference between two dependent intraclass correlation coefficients.
abstract: Inferences for the difference between two dependent intraclass correlation coefficients (ICCs) may arise in studies in which a sample of subjects are each assessed several times with a new device and a standard. The ICC estimates for the two devices may then be compared using a test of significance. However, a confidence interval for a difference between two ICCs is more informative since it combines point estimation and hypothesis testing into a single inference statement. We propose a procedure that uses confidence limits for a single ICC to recover variance estimates needed to set confidence limits for the difference. An advantage of this approach is that it provides a confidence interval that reflects the underlying sampling distribution. Simulation results show that this method performs very well in terms of overall coverage percentage and tail errors. Two data sets are used to illustrate this procedure.
authors.affiliation: Department of Epidemiology and Biostatistics, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ont., Canada N6A 5C1.
authors.forename: Chinthanie F
authors.initials: CF
authors.lastname: Ramasundarahettige
authors.forename: Allan
authors.initials: A
authors.lastname: Donner
authors.forename: G Y
authors.initials: GY
authors.lastname: Zou
mesh_terms: D002986:Clinical Trials as Topic / Q000706:statistics & numerical data; D016001:Confidence Intervals; D003627:Data Interpretation, Statistical; D015233:Models, Statistical; D015203:Reproducibility of Results