Modeling Heterogeneous Variance–Covariance Components in Two-Level Models
Modeling Heterogeneous Variance–Covariance Components in Two-Level Models
Applications of multilevel models to continuous outcomes nearly always assume constant residual variance and constant random effects variances and covariances. However, modeling heterogeneity of variance can prove a useful indicator of model misspecification, and in some educational and behavioral studies, it may even be of direct substantive interest. The purpose …