Old wine in new skins: the sensitivity of established findings to new methods

Findings from an evaluation of a model system for delivering mental health services to youth were reassessed to determine the robustness of key findings to the use of methodologies unavailable to the original analysts. These analyses address a key concern about earlier findings-that the quasi-experimental design involved the comparison of two noncomparable groups. The authors employed propensity score methodology to reconsider between-group baseline differences in observed characteristics of participating families. The authors also considered the possible effect of unobserved between-group differences. The data support previous studies that show few differences in outcomes, but the findings are sensitive to unobserved heterogeneity.