Stability and interpersonal agreement of the interview-based diagnosis of autism

Interpersonal agreement and stability of the Autism Diagnostic Interview-Revised (ADI-R) was examined in this study. Four raters judging 55 subjects agreed moderately to excellently on the items of the diagnostic algorithm, operationalizing the main autistic symptoms according to the classification guidelines of ICD-10 and DSM-IV. When retesting 33 individuals, some items revealed only weak stability. On the level of domains of autistic behavior and diagnosis, the interrater reliability and retest reliability were consistently convincing.