STUDYING MULTIVARIATE CHANGE USING MULTILEVEL MODELS AND LATENT CURVEMODELS

In longitudinal research investigators often measure multiple variable s at multiple points in time and are interested in investigating indiv idual differences in patterns of change on those variables. In the vas t majority of applications, researchers focus on studying change in on e variable at a time. In this article we consider methods for studying relationships between patterns of change on different variables. We s how how the multilevel modeling framework, which is often used to stud y univariate change, can be extended to the multivariate case to yield estimates of covariances of parameters representing aspects of change on different variables. We illustrate this approach using data from a study of physiological response to marital conflict in older married couples, showing a substantial correlation between rate of linear chan ge on different stress-related hormones during conflict. We also consi der how similar issues can be studied using extensions of latent curve models to the multivariate case, and we show how such models are rela ted to multivariate multilevel models.