Gilliam Autism Rating Scale | Third Edition

  • James E. Gilliam
Gilliam Autism Rating Scale, Third Edition (GARS-3) is one of the most widely used instruments for the assessment of autism spectrum disorder in the world. The GARS-3 assists teachers, parents, and clinicians in identifying autism in individuals and estimating its severity

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  • GARS-3 Examiner's Manual (Print)
    9780749166557 Qualification Level B


  • GARS-3 Complete Kit (Print)
    9780749166540 Qualification Level B

    Includes Examiner's Manual, 50 Summary/Response Forms, and the Instructional Objectives Manual, all in a sturdy storage box


  • GARS-3 Summary/Response Forms (Print)
    9780749166564 Qualification Level B

    Pack of 50


  • GARS-3 Instructional Objectives for Individuals Who Have Autism (Print)
    9780749166571 Qualification Level B



Publication date:
Age range:
Individuals 3–22 years old
Qualification level:
Completion time:
5–10 minutes
Scoring options:
Manual scoring

Product Details

The GARS-3 yields standard scores, percentile ranks, severity level, and probability of autism. Items on the GARS-3 are based on the 2013 diagnostic criteria for autism spectrum disorder adopted by the APA.


  • Correlates with other well-known diagnostic tests for autism at magnitude large or very large.
  • Includes all new validity studies that show test results are valid for a wide variety of subgroups, as well as for the general population.
  • Accurately discriminates children with autism spectrum disorder from children without autism (sensitivity = .97, specificity = .97, ROC/AUC = .93).
  • Internal consistency (content sampling) reliability coefficients for the subscales exceed .85 and the Autism Indexes exceed .93.
  • Test-retest (time sampling) reliability coefficients exceed .80 for subscales and .90 for the Autism Indexes.
  • Interrater reliability intraclass coefficients exceed .80 and .84 for the Autism Indexes.


The instrument consists of 56 items grouped into six subscales: Restrictive/Repetitive Behaviors, Social Interaction, Social Communication, Emotional Responses, Cognitive Style, and Maladaptive Speech.

  • Includes four new items.
  • All six subscales have been empirically determined to be valid and sensitive for identification of children with ASD.
  • An interpretation guide provides the examiner with an easy and efficient method for assessing the probability and severity of autism spectrum disorder.
  • A diagnostic validation form is included to ensure test results meet DSM-5 criteria for autism spectrum disorder.
  • Demographic characteristics of the normative sample are keyed to those reported by U.S. Bureau of the Census in 2011.