Assessing children with autism, mental retardation, and typical development using the Playground Observation Checklist.

Elementary school children with normal intelligence and autism (n = 20), mental retardation and no autism (n = 24), and typical development (n = 37) were observed for 15 minutes during recess at school. Ten behaviors were scored as present or absent using the Playground Observation Checklist. Children with autism were distinguished from children with mental retardation and typical development by their social problems, whereas children with typical development and mental retardation did not differ significantly in social competency.