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Validity of the WISC-V Intelligence Testing in Children With Autism Spectrum Disorder

Validity of the WISC-V Intelligence Testing in Children With Autism Spectrum Disorder 1024 575 Mary Bates, PhD

Evaluating thinking and reasoning abilities for children with autism using conventional intelligence tests can be done, but with some caution.

The Wechsler Intelligence Scale for Children, Fifth Edition (WISC-V) is one of the most widely used intelligence tests for children. However, little is known about the validity of this test in children with autism spectrum disorder (ASD).

In a new study published in the Journal of Clinical Child and Adolescent Psychology, researchers from Nationwide Children’s investigated the factor structure and measurement invariance of the WISC-V in a sample of nearly 350 children diagnosed with ASD. Factor analysis is one method of establishing the validity of a test, while measurement invariance is the statistical term for how well a test measures a construct in the same way across groups.

Kevin Stephenson, PhD, a clinical psychologist at Nationwide Children’s and the study’s lead author, says that, overall, their analyses revealed the WISC-V has strong construct validity in children with ASD. The analyses of measurement invariance indicated that the construct of intelligence is structured and measured in a similar way between children with ASD and those without.

“That being said, there is also evidence of statistical bias in some subdomain scores for children with ASD,” says Dr. Stephenson. “Our analysis showed that on subtests of working memory and processing speed, kids with autism, on average, scored lower than kids without autism, even if they had the same overall level of IQ.”

The researchers say that these differences are not due to differences in IQ but to other factors separate from IQ. Dr. Stephenson says that in children with ASD, factors like anxiety or executive function differences could interfere with their performance on certain tests.

This statistical bias means that the full-scale IQ measured by the WISC-V may underrepresent actual cognitive functioning in children with ASD. While the WISC-V may generally be appropriate to use with children with ASD, the authors of the study advise clinicians and researchers to be aware of the potential for biased results, particularly with respect to working memory and processing speed.

Another type of summary score for the WISC-V, called the General Ability Index (GAI), does not include scores from the working memory or processing speed subdomains. Dr. Stephenson and his colleagues report that GAI scores were equally valid for children with autism and those without. The researchers recommend that clinicians routinely report the GAI score and consider it to be an accurate indicator of overall cognitive functioning in children with ASD.

For future studies, Dr. Stephenson says he is interested in identifying predictive tests that could be clinically helpful.

“As psychologists, we don’t just do these tests so we know a child’s score,” he says. “The whole purpose of the psychological evaluation is to inform diagnosis and help us develop specific recommendations for interventions or school accommodations.”

 

Reference:

Stephenson KG, Beck JS, South M, Norris M, Butter E. Validity of the WISC-V in Youth with Autism Spectrum Disorder: Factor Structure and Measurement Invariance. Journal of Clinical Child & Adolescent Psychology. 2021 Jan 15:1-13. doi: 10.1080/15374416.2020.1846543.

Image credit: Adobe Stock

About the author

Mary a freelance science writer and blogger based in Boston. Her favorite topics include biology, psychology, neuroscience, ecology, and animal behavior. She has a BA in Biology-Psychology with a minor in English from Skidmore College in Saratoga Springs, NY, and a PhD from Brown University, where she researched bat echolocation and bullfrog chorusing.

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