This study examined the reliability and validity of the structural section of the Ayres Sensory Integration^® Fidelity Measure© (ASIFM), which provides a method for monitoring the extent to which an intervention was implemented as conceptualized in studies of occupational therapy using sensory integration intervention methods (OT–SI). We examined the structural elements of the measure, including content of assessment reports, availability of specific equipment and adequate space, safety monitoring, and integration of communication with parents and other team members, such as collaborative goal setting with parents or family and teacher education, into the intervention program. Analysis of self-report ratings by 259 occupational therapists from 185 different facilities indicated that the structural section of the ASIFM has acceptable interrater reliability (r ≥ .82) and significantly differentiates between settings in which therapists reportedly do and do not practice OT–SI (p < .001).

OBJECTIVE. We developed a reliable and valid fidelity measure for use in research on Ayres Sensory Integration (ASI) intervention. METHOD. We designed a fidelity instrument to measure structural and process aspects of ASI intervention. Because scoring of process involves subjectivity, we conducted a series of reliability and validity studies on the process section. Raters were trained to score therapist strategies observed in video recordings of adult–child dyads. We examined content validity through expert ratings. RESULTS. Reliability of the process section was strong for total fidelity score (ICC = .99, Cronbach’s α = .99) and acceptable for most items. Total score significantly differentiated ASI from four alternative interventions. Expert ratings indicated strong agreement that items in the structural and process sections represent ASI intervention. CONCLUSION. The Ayres Sensory Integration Fidelity Measure has strong content validity. The process section is reliable and valid when scored by trained raters with expertise in ASI.