GADS Gilliam Asperger’s Disorder Scale

James E. Gilliam, PhD

Purpose: Identifies individuals with unique behavioral problems who may have Asperger’s disorder
Format: Paper and pencil
Age range: 3 years to 22 years
Time: 5-10 minutes

Qualification level: B

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The GADS is used to assess individuals with unique behavioral problems that may indicate a possible diagnosis of Asperger’s disorder.

Items describe specific, observable, measurable behaviors

  • Thirty-two clearly stated items are divided into four subscales; eight additional items regarding their child’s development during the first three years of life are included for parents.
  • Items are based on the most current definitions of Asperger’s disorder.
  • Behaviors are rated using an objective, frequency-based format; standard scores and percentiles are provided.

Information provided can be used to help make a diagnosis

  • Easily completed by a parent and a professional who knows the individual, the GADS provides documentation about the essential behavior characteristics of Asperger’s disorder necessary for diagnosis.
  • Can be used in the assessment process to document behavioral progress, to target goals for IEPs, and for research purposes.
  • Validity was demonstrated by confirming that the items of the test are directly related to the definitions of Asperger’s disorder, the subscales are strongly related to each other and the overall diagnosis of Asperger’s disorder, and the GADS scores discriminate persons with Asperger’s disorder from persons with autism and other behavioral disorders.
  • Normed on a sample of 371 individuals with Asperger’s disorder from the United States, Canada, and Australia.

Additional information


Kits, Manuals, books, and equipment, Forms and booklets


5197-KT GADS Introductory Kit includes GADS Examiner's Manual and 25 Summary/Response Booklets, 5198-TM GADS Examiner's Manual, 5199-RF GADS Summary/Response Booklets (pkg/25)