LAUSR

The Checklist for Autism Spectrum Disorder (CASD) completed by a psychologist (following standardized procedures integrating parent interview data, teacher report, and clinical observations) was compared with the CASD completed independently by mothers and teachers in 168 children with ASD and 40 with ADHD (1–12 years). The 30 CASD autism symptoms are scored as present or absent. Using mother scores 36% of children with ASD scored below the autism diagnostic cutoff, and 75% scored below the cutoff based on teacher scores. Many symptoms deemed present by the psychologist were not reported on the mother and teacher CASD. Mother-teacher correlations indicated little correspondence. Mother and teacher CASD scores should never be used alone. Diagnostic instruments must be administered following standardized procedures.