Multisystemic Therapy: Monitoring Treatment Fidelity*

The challenges of specifying a complex and individualized treatment model and measuring fidelity thereto are described, using multisystemic therapy (MST) as an example. Relations between therapist adherence to MST principles and instrumental and ultimate outcome variables are examined, as are relations between clinical supervision and therapist adherence. The findings provide modest support for the associations between MST adherence measures and instrumental and ultimate outcomes. Results also show that adherence can be altered when clinical supervision and adherence monitoring procedures are fortified. The modest associations between adherence measures and youth outcomes argue for further refinement and validation of the MST adherence measure, especially in light of the well‐established effectiveness of MST with challenging clinical populations and the increasing dissemination of MST programs.