The relative impact of treatment program 'robustness' and 'dosage' on client outcomes.

The relationship between two aspects of program quality (robustness of model implementation and service dosage), client outcomes of self-reported and observer-rated psychosocial functioning, and intensive mental health service utilization costs was examined for 132 persons with dual mental and substance disorders. Membership in the 'robustly implemented' behavioral skills intervention was significantly associated with higher levels of self-reported and observer-rated psychosocial functioning, while membership in the 'robustly implemented' 12-step group was significantly related to higher intensive mental health service costs. Dosage of supportive service exhibited a significant, positive relationship to lower intensive mental health service costs but not to functioning. Although the addition of qualitative data was useful in interpreting the findings from the main study analyses, it had no discernable statistical impact on the regression equations for three major outcome variables.