Lee, Keunbaik; Lee, JungBok; Hagan, Joseph; Yoo, Jae Keun - In: Computational Statistics & Data Analysis 56 (2012) 6, pp. 1545-1551
Generalized linear mixed models (GLMMs) are commonly used to analyze longitudinal categorical data. In these models, we typically assume that the random effects covariance matrix is constant across the subject and is restricted because of its high dimensionality and its positive definiteness....