The planned study will randomly assign aggressive children to one of two versions of the Coping Power child component. The two versions of Coping Power will either deliver the child component of the program in the usual small group format (Group Coping Power: GCP) or in a newly-developed individual format (Individual Coping Power: ICP). By providing a direct comparison of two different formats of the same intervention, the planned study's design will fill a critical gap in our current understanding of the relative effectiveness of group vs. individual programs. Further, this study will allow for examination of the specific factors that influence relative effectiveness of these two formats, important information with broad implications for program development, training of clinicians, and intervention implementation.