(GARS-3) Gilliam Autism Rating Scale, Third Edition

by James E. Gilliam, PhD

(GARS-3) Gilliam Autism Rating Scale, Third Edition

by James E. Gilliam, PhD
Benefits Helps diagnose autism and estimate its severity
Ages 3 to 22 years
Admin time 5 to 10 minutes
Norms Based on a sample of 1,859 individuals representing demographic characteristics of U.S. Census data for 2011
Publish Date 2013
Qualifications Level C required.
About Qualification Levels
HAVE A QUESTION? CALL 800.648.8857

About This Product

Picture of (GARS-3) Gilliam Autism Rating Scale, Third Edition

BY JAMES E. GILLIAM, PHD

The Gilliam Autism Rating Scale, Third Edition (GARS-3) helps clinicians identify autism, assess its severity, and determine appropriate intervention. Items in the third edition of this widely used test reflect criteria for diagnosing Autism Spectrum Disorder (ASD) found in the new Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5).

Fifty-six items clearly describe typical behaviors of individuals with ASD, and are grouped into six subscales:

  • Restrictive and Repetitive Behaviors
  • Social Interaction
  • Social Communication
  • Emotional Responses
  • Cognitive Style
  • Maladaptive Speech

Administration of the GARS-3 provides standard scores, percentile ranks, severity level, and probability of autism.

Reliability and Validity

Internal consistency (content sampling) reliability coefficients exceed .85 for the subscales and .93 for the Autism Indexes. Test-retest (time sampling) reliability coefficients exceed .80 for the subscales and .90 for the Autism Indexes.

Interrater reliability intraclass coefficients exceed .80 and .84 for the Autism Indexes. There is very strong correlation between the GARS-3 scores and those of other widely used diagnostic tests for ASD. All-new validity studies show that test results are valid for a wide variety of subgroups as well as for the general population. Binary classification studies indicate that the GARS-3 can be used to accurately discriminate children with ASD from those without (i.e., sensitivity = .97, specificity = .97, ROC/AUC = .93). Theoretical and empirical validity of the subscales is proven through confirmatory and exploratory factor analysis. More information about the validity of the GARS-3 is included in the Examiner's Manual.

New in the GARS-3

Items and subscales reflecting DSM-5 diagnostic criteria for ASD Diagnostic validation form assuring test results meet DSM-5 criteria for ASD Forty-four new items Six subscales that are valid and sensitive for identification of ASD New norms based on a sample of 1,859 individuals representing demographic characteristics of U.S. Census data for 2011 Interpretation guide offering an easy and efficient method for identifying the presence and severity of ASD

93