Therapist perception of treatment outcome: Evaluating treatment outcomes among youth with antisocial behavior problems.

Effective evaluation of treatment requires the use of measurement tools producing reliable scores that can be used to make valid decisions about the outcomes of interest. Therapist-rated treatment outcome scores that are obtained within the context of empirically supported treatments (ESTs) could provide clinicians and researchers with data that are easily accessible and complimentary to existing instrumentation. We examined the psychometric properties of scores from the Therapist Perception of Treatment Outcome: Youth Antisocial Behavior (TPTO:YAB), an instrument developed to assess therapist judgments of treatment success among families participating in an EST, Multisystemic Therapy (MST), for youth with antisocial behavior problems. Data were drawn from a longitudinal study of MST. The initial 20-item TPTO:YAB was completed by therapists of 111 families at midtreatment and 163 families at treatment termination. Rasch model dimensionality analyses provided evidence for 2 dimensions reflecting youth- and caregiver-related aspects of treatment outcome, although a bifactor analyses suggested that these dimensions reflected a single more general construct. Rasch analyses were also used to assess item and rating scale characteristics and refine the number of items. These analyses suggested items performed similarly across time and that scores reflect treatment outcome in similar ways at mid and posttreatment. Multilevel and zero-order analyses provided evidence for the validity of TPTO:YAB scores. TPTO:YAB scores were moderately correlated with scores of youth and caregiver behaviors targeted in treatment, adding support to its use as a treatment outcome measurement instrument.