The model is based in the concept that juvenile problem behavior stems from faulty genetic/biological endowment, an environment that obstructs growth and development, and deficient interactions between developing organisms and their environments. Given this perspective, the model does not view aggressive, acting-out behavior as an isolated problem that becomes the primary focus of behavioral modification strategies. The model considers excessive aggression as just one among many negative behaviors symptomatic of the fact that the juvenile's environment is not appropriately meeting developmental needs. The therapeutic milieu is structured to minimize undesirable behaviors by providing developmentally appropriate, need-satisfying interventions. This involves a developmental assessment of each resident and the tailoring of group norms and behavioral standards to the developmental levels of the majority of the residents. Adjustments are made for individual developmental differences. 2 figures and 11 references.