A fundamental observation in the social and behavioral sciences is that people change over time, but not necessarily in the same way or at the same rate. For example, verbal ability increases steadily throughout the elementary school years, but it does not increase at the same rate for all students. There are individual differences in the rate and direction of change in many contexts, and these...

doi: 10.3969/j.issn.1002-0829.2012.06.009 Division of Biostatistics, Thomas Jefferson University, Philadelphia, Pennsylvania, USA *Correspondence: [email protected] Psychiatric studies often collect longitudinal data to characterize the natural history of disease in a cohort or to evaluate the effect of behavioral or pharmaceutical interventions. For example, in a recent partially ra...

Learning and development are ubiquitous. When new skills are acquired, when attitudes and interests develop, people change. Measuring change demands a longitudinal perspective, with multiple waves of data collected on representative people at sensibly spaced intervals. Multi-wave data is usually analyzed by individual growth modeling using a multilevel model for change (Singer & Willett, 2003)....

the objective of this study was to estimate variance components and genetic parameters for growth curve parameters in shall sheep. studied traits were parameters of brody growth model which included a (asymptotic mature weight), b (initial animal weight) and k (maturation rate). the data set and pedigree information used in this study were obtained from the animal breeding center of iran and co...