Relations between reading and writing have been studied extensively, but the less is known about the developmental nature of their interrelations. This study applied latent change score modeling to investigate longitudinal relations between reading and writing skills at the word, sentence, and text levels. Latent change score models were used to…

The present study evaluated the stability of math learning difficulties over a 2-year period and investigated several factors that might influence this stability (categorical vs. continuous change, liberal vs. conservative cut point, broad vs. specific math assessment); the prediction of math performance over time and by performance level was also…

Nonlinear growth curves or growth curves that follow a specified nonlinear function in time enable researchers to model complex developmental patterns with parameters that are easily interpretable. In this article we describe how a variety of sigmoid curves can be fit using the M"plus" structural modeling program and the nonlinear…