A MULTIVARIATE HIERARCHICAL MODEL FOR STUDYING PSYCHOLOGICAL CHANGE WITHIN MARRIED-COUPLES

This article illustrates new statistical methods for the study of psyc hological change in married couples. The design involves time-series d ata on each partner. The analysis combines longitudinal methods for st udies of individual change with cross-sectional methods for the study of matched pairs. Each person is viewed as changing over time as a fun ction of an individual growth curve or change function. As in previous studies of individual change, a person's trajectory depends on time-i nvariant personal background characteristics and time-varying changes in the environment. However, unlike typical studies of individual chan ge, a person's changing psychological profile depends, in part, on the influence of that person's partner. These methods apply directly to o ther types of longitudinal studies on families (e.g., studies that use teacher and parent reports of a child's social behavior). The methodo logy is flexible in allowing randomly missing data, varying spacing of time points, unbalanced designs, and time-varying and time-invariant covariates.