Measuring intelligence in Autism and ADHD: Measurement invariance of the-Binet 5th edition and impact of subtest scatter on abbreviated IQ accuracy.
Check routing-subtest scatter on the SB-5 ABIQ—more scatter raises the chance you'll overestimate full-scale IQ in kids with autism or ADHD.
01Research in Context
What this study did
The team gave the Stanford-Binet 5 to kids with autism and kids with ADHD. They checked if the test measures the same skills in both groups. They also looked at how often the short form IQ (ABIQ) guesses the full IQ wrong when the scores jump around.
They used math models to see if the test is fair for both diagnoses. They counted how much each child's scores scattered and linked that scatter to ABIQ mistakes.
What they found
The test worked the same way for autism and ADHD. That means you can compare scores across the two groups.
The ABIQ usually matched the full IQ. Yet when a child's routing subtest scores bounced around a lot, the ABIQ often overshot the real IQ.
How this fits with other research
Coolican et al. (2008) first showed that autistic kids score higher on nonverbal than verbal SB-5 tasks. Dai et al. (2023) now widen that view by adding ADHD and proving the test is fair for both groups.
Koegel et al. (2014) warned that raw Autism Quotient scores can't be compared across groups because the scale lacks scalar invariance. G et al. echo this idea: if scatter breaks invariance on the SB-5, don't trust the ABIQ as a final number.
Bao et al. (2017) found that autism social symptoms, not IQ, predict low adaptive scores. G et al. add that scatter on the IQ test itself can mislead you, so both studies push clinicians to look past the single IQ label.
Why it matters
If you test a child with autism or ADHD, glance at the routing-subtest graph before you write the ABIQ. Wide jumps mean you should give the full battery or note that the short score might overshoot. This keeps you from calling a child average when they may need more support.
Want CEUs on This Topic?
The ABA Clubhouse has 60+ free CEUs — live every Wednesday. Ethics, supervision & clinical topics.
Join Free →Before writing the ABIQ, graph the routing subtests—if scores spread more than one stanine, run the full battery.
02At a glance
03Original abstract
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.
Autism research : official journal of the International Society for Autism Research, 2023 · doi:10.1002/aur.3034