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Gilliam Autism Rating Scale,Third Edition

James E. Gilliam, PhD

Helps you identify and diagnose autism
Paper and pencil
Age range:
3 years to 22 years
5–10 minutes
Qualification level:
A degree from an accredited 4-year college or university in psychology, counseling, speech-language pathology, or a closely related field plus satisfactory completion of coursework in test interpretation, psychometrics and measurement theory, educational statistics, or a closely related area; or license or certification from an agency that requires appropriate training and experience in the ethical and competent use of psychological tests. Close

One of the most widely used instruments for the assessment of autism spectrum disorder (ASD) in the world, the GARS assists teachers, parents, and clinicians in identifying ASD in individuals and estimating its severity.

Features and benefits

  • Items and subscales reflect DSM-5 diagnostic criteria for ASD.
  • Items are grouped into three subscales—Stereotyped Behaviors, Communication, and Social Interaction.

Test structure

  • Fifty-six clearly stated items describe the characteristic behaviors of persons with ASD and are grouped into six subscales: Restrictive, Repetitive Behaviors, Social Interaction, Social Communication, Emotional Responses, Cognitive Style, and Maladaptive Speech.
  • An interpretation guide allows the examiner an easy and efficient method for assessing the probability and severity of ASD.

Technical information

  • Internal consistency reliability coefficients exceed .85 for the subscales, .93 for the Autism Indexes; test-retest reliability coefficients exceed .80 for subscales and .90 for the Autism Indexes.
  • Correlations of the GARS-3 scores with those of other well-known diagnostic tests for autism are large or very large in magnitude.
  • Binary classification studies indicate that the GARS-3 is able to accurately discriminate children with ASD from children without (i.e., sensitivity = .97, specificity = .97, ROC/AUC = .93).
  • Normative data (N = 1,859) were collected in 2010 and 2011. Demographic characteristics of the normative sample are representative of 2011 U.S. Census statistics. 

Online Scoring and Report System

Access to the GARS-3 Online Scoring and Report System is included with the purchase of each GARS-3 Complete Kit and with the purchase of every replacement pack of Summary/Response Forms. This scoring and report system was designed as a quick, efficient tool for entering individual or group test session data; scoring subtest item responses; converting the total raw scores into standard scores and percentile ranks; generating index scores and percentile ranks, and obtaining a score summary and narrative report.  The GARS-3 Summary/Response Forms that come with the kit and are sold separately include the instructions for activating the online scoring account.  The activation code for online scoring is printed on each form.