Used multivariate latent growth modeling to conceptualize and analyze intra-individual changes in children's social skills and intraindividual differences in these changes in home and school settings for 378 children from kindergarten to grade 3. Results suggest that the nature of the intraindividual change in children's social skills may be…

Repeated measures and longitudinal studies arise often in social and behavioral science research. During the planning stage of such studies, the calculations of sample size are of particular interest to the investigators and should be an integral part of the research projects. In this article, we consider the power and sample size calculations for…