Examining the Impact of Treatment Fidelity on Client Outcomes in a Statewide Implementation of Parent-Child Interaction Therapy

Clinician treatment fidelity, consisting of treatment adherence and clinician competence, is commonly assessed during the implementation of evidence-based treatments to ensure that clinicians are delivering care according to an intended service model. Although resources are often expended in fidelity measurement, associations between fidelity and client outcomes has not been well established in the psychotherapy literature. The relationship between clinician fidelity and treatment outcomes was investigated in a longitudinal sample of clinicians (n = 17) and parent-child dyads (n = 32) following a statewide implementation of Parent-Child Interaction Therapy. Observer-rated measures of adherence and coaching competence collected from early treatment sessions were used to predict intake levels and growth trajectories of parent-reported behavior problems and positive parenting skills. Hierarchical linear modeling results indicated that higher levels of coaching competence were associated with greater behavior problem frequency at intake. Neither early session adherence nor early session competence, as they were measured in the current study, predicted changes in treatment outcomes over time. These results suggest that additional variables should be modeled alongside early treatment fidelity to predict treatment outcome change. Possible explanations for these findings, limitations of the current study, and directions for future research are discussed.