This manuscript by Connell and Frye ("Infant Child Dev" 2006; 15(6): 609-621) provides a clear example of the application of latent growth mixture models (LGMM) to the development of antisocial behaviour in adolescence. The LGMM approach is discussed in the context of this example, and factors influencing the results achieved with these methods are highlighted. Overall, developmental psychologists have much to gain from the use of these new approaches.