The Childhood Autism Rating Scale (CARS), (Schopler et al. in J Autism Dev Disord 10(1):91-103, 1980) is a 15-item observation-based rating scale that yields a total score reflective of autism symptom severity. This study investigated the factor structure of the CARS in a sample of 2-year-old children with DSM-IV-TR (American Psychiatric Association in Diagnostic and statistical manual of mental disorders, 4th edn. American Psychiatric Publishing, Washington, 2000) diagnoses of AD or PDD-NOS. Following a preliminary internal cross-validation, principal axis factor analysis was completed (N = 282). The results indicate a three-factor solution: Social Communication, Stereotyped Behaviors and Sensory Sensitivities, and Emotional Reactivity. The factors are meaningful, with the first two reflective of DSM-5 symptom domains. This study supports the continued relevance of the CARS in ASD assessment, and extends its utility in 2-year-old children.
Keywords: ASD assessment; CARS; Factor analysis.