What Has Been Learned from Group-Based Trajectory Modeling? Examples from Physical Aggression and Other Problem Behaviors

The focus of this article is group-based trajectory modeling. Its purpose is threefold. The first is to clarify the proper statistical interpretation of a trajectory group. The second is to summarize some key findings on the developmental course of aggression and other problem behaviors that have emerged from the application of group-based trajectory models and that in the authors' judgment are important to the fields of developmental criminology and developmental psychopathology. The third is to lay out some guidelines on the types of problems for which use of group-based trajectory modeling may be particularly productive.