Analysis of longitudinal data within accelerated longitudinal designs

Using latent growth curve methodology and combining information from 4 different overlapping age cohorts, each measured at 1-year intervals over a 3-year period, a single developmental trajectory for adolescent alcohol use was formed spanning 12-17 years of age (N = 461). At the same time, data collected from the same study sample on a single cohort (N = 81) over 6 annual assessments (ages 12-17) was examined to determine whether the accelerated design adequately approximated the developmental trend within a true longitudinal design observed over 6 years of data collection. Comparison of separate models and a combined multisample model revealed no significant differences between the 2 designs in their representation of initial status and growth, as well as similar effects for the covariates of gender, deviance, and parent alcohol use on initial status and growth.