We illustrate the use of formative and summative assessment in evaluating a therapeutic classroom program for children with serious emotional disturbances. Information was analyzed based on data gathered for clinical decision-making during treatment (formative assessment) and measurement of outcomes at discharge (summative assessment) from a school-based Intensive Mental Health Program. Results indicated that overall ratings of daily indicators of behavior across all environments (therapeutic classroom, neighborhood school, and home) were predictive of functioning at discharge. An ecological approach during the formative assessment period of evaluation is important as compared to only examining individual environments. Formative assessment techniques can predict scores on a summative assessment measure. Thus, we found supportive evidence for the formative and summative procedures used in the Intensive Mental Health Program for therapeutic interventions, clinical decision-making, and outcomes assessment.