GARS-3:
The Gilliam Autism Rating Scale,Third Edition
If your child is being evaluated for autism, you may come across the GARS-3 – a widely used autism rating scale. Understanding what it is and how it works can help you feel more informed and prepared as you navigate the diagnostic process.
What Is the GARS-3?
The Gilliam Autism Rating Scale, Third Edition (GARS-3) is a standardized, norm-referenced assessment tool designed to help clinicians identify autism spectrum disorder (ASD) and estimate its severity. Developed by Dr. James E. Gilliam and published in 2014, it is one of the most widely used instruments for autism assessment in the world.
The GARS-3 is aligned with the DSM-5 diagnostic criteria for autism spectrum disorder and is designed for individuals aged 3 through 22 years. Often completed by clinicians, the GARS-3 measures how autism presents itself in children and young adults based on observations of behavior over time. Administration typically takes just 5–10 minutes, making it one of the most efficient tools in the autism assessment process.
What Does the GARS-3 Assess?
Restrictive/Repetitive Behaviors:
Social Interaction:
Social Communication:
Emotional Responses:
Cognitive Style:
Maladaptive Speech:
Together, these subscales provide a comprehensive picture of how autism manifests in a specific individual, helping clinicians determine not just whether autism is present, but how significantly it affects daily functioning.
What Does GARS-3 Results Tell Us?
Using a 4-point scale ranging from 0 (not at all like the individual) to 3 (very much like the individual), the GARS-3 produces several key scores:
Standard scores and percentile ranks:
Autism Index:
Severity level:
Probability of autism:
How Is the GARS-3 Used in the Diagnostic Process?
The GARS-3 is typically used as one part of a comprehensive autism evaluation, alongside direct observation tools like the ADOS-2, developmental history, and parent interviews. It is particularly valuable because it captures behaviors observed across multiple settings and over time, giving clinicians a broader picture than a single observation session can provide.
The GARS-3 is also used to track progress over time, helping clinicians and families see how behaviors change in response to autism intervention, like ABA therapy.
Who Administers the GARS-3?
The GARS-3 is often administered, scored, and interpreted by a qualified clinician – typically a licensed psychologist or neuropsychologist – as part of a broader diagnostic evaluation.
At Behavior Frontiers, our trusted network of licensed diagnostic partners uses a variety of validated assessment tools – which may include the GARS-3 – as part of comprehensive autism evaluations for families who are ready to begin ABA therapy with Behavior Frontiers if diagnosed.
GARS-3 And ABA Therapy with Behavior Frontiers
At Behavior Frontiers, every child's ABA therapy plan is built around a thorough understanding of their unique profile – informed by comprehensive assessments which may include the GARS-3 – and developed by a licensed BCBA to address each child's specific strengths and needs.
FAQs
The GARS-3 (Gilliam Autism Rating Scale, Third Edition) is a standardized autism rating scale used to identify autism spectrum disorder and estimate its severity in individuals aged 3 through 22 years.
The GARS-3 is typically completed licensed providers based on observed behaviors over time. It is then scored and interpreted on a 4-point scale ranging from 0 (Not at all like the individual) to 3 (Very much like the individual).
The GARS-3 typically takes 5–10 minutes to complete, making it one of the most efficient autism rating scales available. While the GARS-3 assessment is quick, it’s also important to note that a full autism diagnosis cannot be made from the GARS-3 alone and is often just one of the many tools and assessments used to provide an autism diagnosis.
No. The GARS-3 is just one tool used as part of a comprehensive autism evaluation, and the GARS-3 alone is not enough to provide an autism diagnosis. A formal autism diagnosis is made by a licensed clinician based on the full evaluation.
The GARS-3 is designed for individuals aged 3 through 22 years.
The ADOS-2 involves direct observation of your child by a trained clinician. The GARS-3 is a rating scale that is scored based on observed behaviors over time. Most comprehensive evaluations use multiple tools together for the most complete and accurate picture.
