Measuring intelligence in Autism and ADHD: Measurement invariance of the-Binet 5th edition and impact of subtest scatter on abbreviated IQ accuracy.

Researchers tested whether a shortened IQ test works well for children with autism or ADHD. They found the test measures intelligence similarly in both groups. However, when children's scores varied widely across different parts of the test, the shortened version was less accurate and sometimes gave scores that were too high. The study suggests autism and ADHD children have more similar thinking patterns than previously thought.

This study examined cognitive testing accuracy in 1,679 youth (ages 2-16) with autism spectrum disorder (ASD) or ADHD using the Stanford-Binet 5th edition intelligence test. Researchers investigated whether the abbreviated IQ test (ABIQ) measures intelligence similarly across both conditions and how subtest score variability (scatter) affects accuracy. Results showed the test measures IQ consistently in both ASD and ADHD groups, with no significant differences in scatter patterns between diagnoses. However, higher scatter was associated with reduced accuracy of abbreviated IQ scores and tendency to overestimate full-scale IQ scores, regardless of diagnosis.

The findings suggest more similarities than differences between ASD and ADHD cognitive profiles.

Clinicians should interpret abbreviated IQ scores cautiously when subtest scatter is present, regardless of whether the child has ASD or ADHD. Consider using full-scale assessments when scatter is evident to ensure accurate cognitive evaluation and appropriate intervention planning.

Study metadata indicates sample size and detailed methodology are not fully reported. The abstract does not specify demographic characteristics beyond age and gender distribution, limiting generalizability assessment.

Scatter and heterogeneity in cognitive profiles is thought to be common in autism spectrum disorder (ASD), which may indicate differences in the construct of IQ. However, less research has investigated IQ scatter in attention-deficit/hyperactivity disorder (ADHD). Scatter is also thought to negatively impact the predictive validity of IQ summary scores, although there is research refuting this notion. Abbreviated IQ tests, such as the Stanford-Binet fifth edition (SB-5) abbreviated battery IQ (ABIQ), may be especially susceptible to the influence of scatter.

We tested the measurement invariance of the SB-5 as well as the predictive validity of the ABIQ in predicting FSIQ in 1679 youth (21% female) ages 2-16 years with a clinical diagnosis of ASD or ADHD. Results indicated the SB-5 is measuring IQ the same way in ASD and ADHD. There were no differences between diagnostic groups in scatter between ABIQ (i.e., routing) subtests. Additionally, scatter was not related to dimensional autistic traits.

Higher degree of scatter was associated with poorer predictive validity of the ABIQ and a higher likelihood of overestimating FSIQ, regardless of diagnosis. Overall, we found more similarities than differences between the ASD and ADHD groups. Our results show that the SB-5 ABIQ is generally a strong predictor of FSIQ in youth with neurodevelopmental disorders. However, the use of the SB-5 ABIQ in research and clinical applications, without consideration of scatter on routing subtests, is potentially problematic.