My main research interests are in the areas of longitudinal data analysis (e.g., methods and models for studying intra-individual change, variability, and relations, and inter-individual differences in them), multilevel modeling (e.g., dyadic data analysis), structural equation modeling (e.g., mediation analysis), and study design issues (e.g., sample size determination). I am also interested in measurement issues related to longitudinal research. Substantively, I am interested in applying quantitative methods in developmental, family, health, and educational research.