title: Partial likelihood analysis of within-unit variances in repeated measurement experiments.
abstract: The objectives of some experiments are to compare the variances of two or more treatments, products, or techniques. If the investigator is more concerned about within-unit variances rather than between-unit variances, then a repeated measurement design is needed. We invoke a random effects model with heterogeneous within-unit variances for certain repeated measurement designs. We do not impose any distributional assumptions for the random effects, whereas we assume either a normal or multivariate t distribution for the random errors. We propose a partial likelihood analysis for population-based inference and individual-based inference. We illustrate the methodology with an example from a trial comparing serum cholesterol measurements from a routine laboratory analyzer to those of a standardized method.
authors.affiliation: Center for Biostatistics & Epidemiology, College of Medicine, Pennsylvania State University, Hershey 17033, USA.
authors.forename: V M
authors.initials: VM
authors.lastname: Chinchilli
authors.forename: J D
authors.initials: JD
authors.lastname: Esinhart
authors.forename: W G
authors.initials: WG
authors.lastname: Miller
mesh_terms: D000704:Analysis of Variance; D001699:Biometry / Q000379:methods; D016022:Case-Control Studies; D002784:Cholesterol / Q000097:blood; D002986:Clinical Trials as Topic / Q000379:methods; D006801:Humans; D008433:Mathematics; D008722:Methods; D015233:Models, Statistical; D015999:Multivariate Analysis; D011336:Probability; D011897:Random Allocation
chemical_list: D002784:Cholesterol