Forecasting treatment outcomes is essential to improving service delivery. Hierarchical linear modeling was used to construct behavioral change trajectories and help predict treatment responsiveness for 97 partial hospitalization children. Overall, children evidenced statistically significant improvement in psychiatric symptomatology. Younger age, female gender, number of previous out-of-home placements, and lower IQ scores were associated with increased psychopathology and poorer treatment response. Properly configured day treatment can provide an effective organizing platform for implementing complex treatment regimes.