Development of a fidelity measure for research on the effectiveness of the Ayres Sensory Integration intervention.

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 alpha = .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.