title: A new parsimonious model for ordinal longitudinal data with application to subjective evaluations of a gastrointestinal disease.
abstract: In this paper, a new discrete statistical model for ordered categorical data is proposed via fixed-point discretization of a beta latent variable. The resulting discretized beta distribution has a highly flexible shape and it can be either over-dispersed or under-dispersed with respect to the binomial distribution. It has only two parameters, which may therefore parsimoniously depend on covariates and on random effects, providing new tools for the analysis of structured, clustered or longitudinal ordinal data. Practical examples and advices are given and an application of the new model to subjective evaluations of a gastrointestinal disease is shown.
authors: 1 INSERM, UMRS 1138, Team 22, CRC, University Paris 5, University Paris 6, Paris, France.|2 Department of Mathematical Sciences, Politecnico di Torino, Turin, Italy.
authors: Moreno
authors: M
authors: Ursino
authors: 1 INSERM, UMRS 1138, Team 22, CRC, University Paris 5, University Paris 6, Paris, France.
authors: Mauro
authors: M
authors: Gasparini
mesh_terms: D016010:Binomial Distribution; D004415:Dyspepsia / Q000175:diagnosis / Q000453:epidemiology; D005767:Gastrointestinal Diseases / Q000175:diagnosis* / Q000453:epidemiology; D006801:Humans; D016013:Likelihood Functions; D008137:Longitudinal Studies; D015233:Models, Statistical
keywords: Longitudinal data; beta distribution; mixed effect model; ordinal data; ordinal regression