Repeated Measures Analysis with Clustered Subjects

Repeated measures can occur on subjects that are nested within clusters. The clusters may be considered a random effect. Then the covariance structure must accommodate between-cluster variance as well as within-cluster covariance. There also may be higher levels of clustering. In addition, there may be other fixed effect factors that are crossed with some or all of the random effects. The covariance structure must be built into a statistical for the data and the statistical model must be translated into the language of computer software that has capabilities to make computations for statistical data analysis.