RESUMEN
The measurement of treatment adherence (a component of treatment integrity defined as the extent to which a treatment is delivered as intended) is a critical element in treatment evaluation research. This article presents initial psychometric data for scores on the Cognitive-Behavioral Therapy Adherence Scale for Youth Anxiety (CBAY-A), an observational measure designed to be sensitive to common practice elements found in individual cognitive-behavioral therapy (ICBT) for youth anxiety. Therapy sessions (N = 954) from 1 efficacy and 1 effectiveness study of ICBT for youth anxiety were independently rated by 2 coders. Interrater reliability (as gauged by intraclass correlation coefficients) for the item scores averaged 0.77 (SD = 0.15; range .48 to .80). The CBAY-A item and scale (skills, model, total) scores demonstrated evidence of convergent and discriminant validity with an observational measure of therapeutic interventions and an observational measure of the alliance. The CBAY-A item and scale scores also discriminated between therapists delivering ICBT in research and practice settings and therapists delivering nonmanualized usual clinical care. We discuss the importance of replicating these psychometric findings in different samples and highlight possible application of an adherence measure in testing integrity-outcome relations.