The purpose of this study was to: (1) confirm the factor structure of a therapist-report measure of adaptations to an autism evidence-based intervention (EBI), (2) identify predictors of adaptation types, and (3) examine associations of adaptation types with observed therapist fidelity. Participants included a subset of therapists (N = 70; 31.4% Hispanic), autistic children (N = 79; ages 5–13 years; 57.0% Hispanic), and their caregivers (N = 77; 54.5% Hispanic), who participated in the training condition of a community effectiveness trial of An Individualized Mental Health Intervention for Autism (AIM HI). Families reported demographics and completed assessments of child functioning and caregiver strain at baseline. Therapists submitted video recordings of psychotherapy sessions during EBI training, which were later coded for fidelity by independent raters. Therapists completed the Adaptations to Evidence-Based Practices Scale at the end of the 6-month training period. Multi-level confirmatory factor analysis yielded two adaptation types consistent with prior research: Augmenting and Reducing/Reordering adaptations. In multi-level models, higher Augmenting adaptations were associated with lower child cognitive functioning (B= -0.01, p < .05), higher child autism characteristics (B = 0.01, p < .05), and Non-Hispanic White caregiver ethnicity (B = − 0.17, p < .01). Higher Reducing/Reordering adaptations were associated with Non-Hispanic White caregiver race/ethnicity only (B = − 0.33, p < .01). There were no significant associations between therapist-reported adaptations and observed fidelity. This study further supports Augmenting and Reducing/Reordering as distinct subtypes of adaptations with unique predictors. Therapists likely adapt AIM HI to tailor the EBI to individual client needs and do so in ways that do not appear to interfere with fidelity.
Trial Registration ClinicalTrials.gov identifier NCT02416323.