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…

This study investigated whether individual change over time in mathematics and language differs from student to student and whether individual parameters of each of these domains were related within domain. The study also attempted to gain an understanding of individual change in student academic achievement through the application of one of the…