Using the Childhood Autism Rating Scale to Diagnose Autism Spectrum Disorders

  • Colby ChlebowskiEmail author
  • James A. Green
  • Marianne L. Barton
  • Deborah Fein
Original Paper


This study investigated the childhood autism rating scale (CARS) as a tool for ASD diagnoses for 2-year-old (n = 376) and 4-year-old (n = 230) children referred for possible autism. The cut-off score to distinguish autistic disorder from PDD-NOS was 32 in the 2-year-old sample (consistent with Lord in J Child Psychol Psychiatry Allied Discipl, 36, 1365–1382, 1995), and 30 in the 4-year-old sample, with good sensitivity and specificity at both ages. The cut-off score to distinguish ASD from non-ASD at both ages was 25.5, with good sensitivity and specificity. Results confirm the utility of the CARS in distinguishing autistic disorder from PDD-NOS, and distinguishing ASD from other developmental disorders and typical development and suggest that an ASD cutoff around 25, which is in common clinical use, is valid.


Autism spectrum disorders Childhood autism rating scale Diagnosis PDD-NOS 



We would like to thank all the children and families who participated in our study. We gratefully acknowledge the assistance of participating pediatricians and staff in their offices, as well as providers in the Connecticut and Massachusetts Birth-to-Three Early Intervention systems. We would like to thank Jillian Wood, Executive Director of the Hezekiah Beardsley Chapter of the American Academy of Pediatrics, who assisted in recruiting participating physician offices and promoted the study state-wide. We would also like to extend sincere thanks to members of the Early Detection Advisory Board, especially Ho-Wen Hsu, M.D., and Mark Greenstein, M.D., for their wise advice and support. Clinicians Thyde Dumont-Mathieu, Sarah Hodgson, and Jamie Kleinman, graduate students Hilary Boorstein, Alyssa Verbalis, Katelin Carr, Lauren Herlihy, and Kelley Knoch, and our dedicated undergraduate research assistants were invaluable in conducting all aspects of the study. This study is supported by NIH grant R01 HD039961 and Maternal and Child Health Bureau grant R40 MC00270 and prior grants from the National Association for Autism Research, NIMH, and the Department of Education. This paper was prepared from the masters thesis of Colby Chlebowski at the University of Connecticut.


  1. Adrien, J., Perrot, A., Sauvage, D., Leddet, I., Larmande, C., & Barthelemy, C. (1992). Early symptoms in autism from family home movies. Evaluation and comparison between 1st and 2nd year of life using I.B.S.E. scale. Acta Paedopsychiatrica, 55(2), 71–75.PubMedGoogle Scholar
  2. American Psychiatric Association. (2000). Diagnostic and statistical manual of mental disorders (4th ed.). Washington, DC: American Psychiatric Association. (Text revision).Google Scholar
  3. Baron-Cohen, S., Allen, J., & Gillberg, C. (1992). Can autism be detected at 18 months? The needle, the haystack, and the CHAT. The British Journal of Psychiatry, 161(6), 839–843.CrossRefPubMedGoogle Scholar
  4. Buitelaar, J., Van der Gaag, R., Klin, A., & Volkmar, F. (1999). Exploring the boundaries of pervasive developmental disorder not otherwise specified: Analyses of data from the DSM-IV autistic disorder field trial. Journal of Autism and Developmental Disorders, 29, 33–43.CrossRefPubMedGoogle Scholar
  5. Chakrabarti, S., & Fombonne, E. (2001). Pervasive developmental disorders in preschool children. Journal of the American Medical Association, 285, 3093–3099.CrossRefPubMedGoogle Scholar
  6. Charman, T., & Baron-Cohen, S. (2006). Screening for autism spectrum disorders in populations: Progress, challenges, and questions for future research and practice. In T. Charman & W. Stone (Eds.), Social and communication development in autism spectrum disorders (pp. 63–82). New York: Guilford Press.Google Scholar
  7. Chlebowski, C., Barton, M., Hodgson, S., & Fein, D. (2008). Does the CARS cutoff score influence agreement among diagnostic instruments for autism spectrum disorders and clinical judgment in preschool aged children? Poster presented at the meeting of the American Academy of Clinical Neuropsychology, Boston, MA.Google Scholar
  8. Chlebowski, C., Barton, M., Hodgson, S., & Fein, D. (2009). Diagnostic stability of autism spectrum disorder diagnoses made before age 2. Poster presented at the International Meeting for Autism Research, Chicago, Illinois.Google Scholar
  9. Cicchetti, D. (1994). Guidelines, criteria, and rules of thumb for evaluating normed and standardized assessment instruments in psychology. Psychological Assessment, 6, 284–290.CrossRefGoogle Scholar
  10. Cicchetti, D., & Sparrow, S. (1981). Developing criteria for establishing interrater reliability of specific items: applications to assessment of adaptive behavior. American Journal of Mental Deficiency, 86, 127–137.PubMedGoogle Scholar
  11. Cicchetti, D. V., Volkmar, F., Klin, A., & Showalter, D. (1995). Diagnosing autism using ICD-10 criteria: A comparison of neural networks and standard multivariate procedures. Child Neuropsychology, 1, 26–37.CrossRefGoogle Scholar
  12. de Bildt, A., Sytema, S., Ketelaars, C., Kraijer, D., Mulder, E., Volkmar, F., et al. (2004). Interrelationship between Autism Diagnostic Observation Schedule-Generic (ADOS-G), Autism Diagnostic Interview-Revised (ADI-R), and the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) classification in children and adolescents with mental retardation. Journal of Autism and Developmental Disorders, 34, 129–137.CrossRefPubMedGoogle Scholar
  13. Eaves, R., & Milner, B. (1993). The criterion-related validity of the childhood autism rating scale and the autism behavior checklist. Journal of Abnormal Child Psychology, 21, 481–491.CrossRefPubMedGoogle Scholar
  14. Filipek, P., Accardo, P., Baranek, G., Cook, E., Dawson, G., Gordon, B., et al. (1999). The screening and diagnosis of autistic spectrum disorders. Journal of Autism and Developmental Disorders, 29, 437–482.CrossRefGoogle Scholar
  15. Kleinman, J., Ventola, P., Pandey, J., Verbalis, A., Barton, M., Hodgson, S., et al. (2008). Diagnostic stability in very young children with autism spectrum disorders. Journal of Autism and Developmental Disorders, 38, 606–615.CrossRefPubMedGoogle Scholar
  16. Klin, A., Lang, J., Cicchetti, D., & Volkmar, F. (2000). Brief report: Interrater reliability of clinical diagnosis and DSM IV criteria for autistic disorder: Results of the DSM IV Field Trial. Journal of Autism and Developmental Disorders, 30, 163–167.CrossRefPubMedGoogle Scholar
  17. Lord, C. (1995). Follow-up of two-year-olds referred for possible autism. Journal of Child Psychology and Psychiatry and Allied Disciplines, 36, 1365–1382.CrossRefGoogle Scholar
  18. Lord, C., Risi, S., Lambrecht, L., Cook, E. H. J., Leventhal, B. L., DiLavore, P. C., et al. (2000). The autism diagnostic observation schedule-generic: A standard measure of social and communication deficits associated with the spectrum of autism. Journal of Autism and Developmental Disorders, 30, 205–223.CrossRefPubMedGoogle Scholar
  19. Lord, C., Storoschuk, S., Rutter, M., & Pickles, A. (1993). Using the ADI-R to diagnose autism in preschool children. Infant Mental Health Journal, 14, 234–252.CrossRefGoogle Scholar
  20. Luteijn, E., Serra, M., Jackson, S., Steenhuis, M., Althaus, M., Volkmar, F., et al. (2000). How unspecified are disorders of children with a pervasive developmental disorder not otherwise specified? A study of social problems in children with PDD-NOS and ADHD. European Child and Adolescent Psychiatry, 9, 168–179.CrossRefPubMedGoogle Scholar
  21. Matson, J., & Boisjoli, J. (2007). Differential diagnosis of PDD-NOS in children. Research in Autism Spectrum Disorders, 1, 75–84.CrossRefGoogle Scholar
  22. Mullen, E. M. (1995). Mullen scales of early learning: AGS edition. Circle Pines, MN: American Guidance Service.Google Scholar
  23. Nordin, V., Gillberg, C., & Nydén, A. (1998). The Swedish version of the childhood autism rating scale in a clinical setting. Journal of Autism and Developmental Disorders, 28, 69–75.CrossRefPubMedGoogle Scholar
  24. Perry, R. (1998). Misdiagnosed ADD/ADHD: Rediagnosed PDD. Journal of the American Academy of Child & Adolescent Psychiatry, 37, 113–114.CrossRefGoogle Scholar
  25. Perry, A., Condillac, R., Freeman, N., Dunn-Geier, J., & Belair, J. (2005). Multi-site study of the childhood autism rating scale (CARS) in five clinical groups of young children. Journal of Autism and Developmental Disorders, 35, 625–634.CrossRefPubMedGoogle Scholar
  26. Perry, A., & Freeman, N. (1996). Psychometric properties of the Childhood Autism Rating Scale (CARS). Poster presented at the Ontario Association on Developmental Disabilities Research Special Interest Group Research Day, Toronto, ON.Google Scholar
  27. Rellini, E., Tortolani, D., Trillo, S., Carbone, S., & Montecchi, F. (2004). Childhood autism rating scale (CARS) correspondence and conflicts with DSM-IV criteria in diagnosis of autism. Journal of Autism and Developmental Disorders, 34, 703–708.CrossRefPubMedGoogle Scholar
  28. Risi, S., Lord, C., Gotham, K., Corsello, C., Chrysler, C., Szatmari, P., et al. (2006). Combining information from multiple sources in the diagnosis of autism spectrum disorders. Journal of the American Academy of Child & Adolescent Psychiatry, 45, 1094–1103.CrossRefGoogle Scholar
  29. Robins, D., Fein, D., Barton, M., & Green, J. (2001). The modified checklist for autism in toddlers: An initial study investigating the early detection of autism and pervasive developmental disorders. Journal of Autism and Developmental Disorders, 31, 131–144.CrossRefPubMedGoogle Scholar
  30. Saemundsen, E., Magnusson, P., Smari, J., & Sigurdarddottir, S. (2003). Autism diagnostic interview—revised and the childhood autism rating scale: Convergence and discrepancy in diagnosing autism. Journal of Autism and Developmental Disorders, 33, 319–328.CrossRefPubMedGoogle Scholar
  31. Schopler, E., Reichler, R., & DeVellis, R. (1980). Toward objective classification of childhood autism: Childhood autism rating scale (CARS). Journal of Autism and Developmental Disorders, 10, 91–103.CrossRefPubMedGoogle Scholar
  32. Schopler, E., Reichler, R., & Rochen Renner, B. (1988). The childhood autism rating scale. Western Psychological Services.Google Scholar
  33. Spitzer, R., & Siegel, B. (1990). The DSM-III-R field trial of pervasive developmental disorders. Journal of the American Academy of Child & Adolescent Psychiatry, 29, 855–862.CrossRefGoogle Scholar
  34. Stone, W., Lee, F., Ashford, L., Brisie, J., Hepburn, S., & Coonrod, E. (1999). Can autism be diagnosed accurately in children under three? Journal of Child Psychiatry Psychology and Allied Disciplines, 40, 219–226.CrossRefGoogle Scholar
  35. Tachimori, H., Osada, H., & Kurita, H. (2003). Childhood autism rating scale-Tokyo version for screening pervasive developmental disorders. Psychiatry and Clinical Neuroscience, 57, 113–118.CrossRefGoogle Scholar
  36. Tidmarsh, L., & Volkmar, F. (2003). Diagnosis and epidemiology of autism spectrum disorders. The Canadian Journal of Psychiatry/La Revue canadienne de psychiatrie, 48, 517–525.Google Scholar
  37. Ventola, P., Kleinman, J., Pandey, J., Barton, M., Allen, S., Green, J., et al. (2006). Agreement among four diagnostic instruments for autism spectrum disorders in toddlers. Journal of Autism and Developmental Disorders, 36, 839–847.CrossRefPubMedGoogle Scholar
  38. Volkmar, F., Klin, A., Siegel, B., & Szatmari, P. (1994). Field trial for autistic disorder in DSM-IV. American Journal of Psychiatry, 151, 1361–1367.PubMedGoogle Scholar

Copyright information

© Springer Science+Business Media, LLC 2010

Authors and Affiliations

  • Colby Chlebowski
    • 1
    Email author
  • James A. Green
    • 1
  • Marianne L. Barton
    • 1
  • Deborah Fein
    • 1
  1. 1.Department of PsychologyUniversity of ConnecticutStorrsUSA

Personalised recommendations