This study proposes a two-stage causal modeling with instrumental variables to mitigate selection bias, provide correct standard error estimates, and address nonnormal and missing data issues simultaneously. Bayesian methods are used for model estimation. Robust methods with Student's "t" distributions are used to account for nonnormal…

This study attempts to identify different patterns of cognitive growth in kindergarten and first grade associated with selected subpopulations. The results are based upon a nationally representative sample of fall kindergartners who were retested in the spring of their kindergarten year and then again in the fall and spring of their first grade…