Transition models for binary data / Modelos de transição para dados binários
AUTOR(ES)
Idemauro Antonio Rodrigues de Lara
DATA DE PUBLICAÇÃO
2007
RESUMO
Binary or dichotomous data are quite common in many fields of Sciences in which there is an interest in registering the occurrence of a particular event. On the other hand, when each sampled unit is evaluated in more than one occasion, we have longitudinal data or repeated measures over time. It is also common, in longitudinal studies, to have explanatory variables associated to response measures, which can be time dependent or independent. In the literature, there are many approaches to modeling and evaluating these data, where the models are extensions of generalized linear models. This work focus on generalized linear transition models suitable for analyzing longitudinal data with binary response. Such models are based on stochastic processes and we aim to model the probabilities of change or transitions of individual response categories in time. The most used assumption in these processes is the Markov property, in which the response in one occasion depends on the immediately preceding response. Thus we review the fundamentals to specify these models, showing the diferences between stationary and non-stationary processes. The maximum likelihood approach is used in order to fit the models and estimate the probabilities. Furthermore, we show asymptotic tests to compare treatments based on odds ratio and on the diferences of transition probabilities. We also present a combination of random-efects model with transition model. The methods are illustrated with health data. For these data, the process is stationary of order two and the suggested test points to a significant statistical diference in favor of the active treatment. This work is an initial approach to transition models, which have high applicability and are great sources for further studies and researches.
ASSUNTO(S)
generalized linear model stochastic processes verossimilhança likelihood análise de dados longitudinais modelos lineares generalizados processos estocásticos analysis of longitudinal data
