Brief report: The level and nature of autistic intelligence revisited.
Stick with Wechsler for high-functioning autism; only use Raven's if Wechsler IQ is below 85.
01Research in Context
What this study did
Bölte et al. (2009) compared two IQ tests in people with autism. One test is the Wechsler IQ battery. The other is Raven's Progressive Matrices.
They looked at who scored higher on which test. They also checked if the gap changed when the Wechsler score was low or high.
What they found
Only the group with low Wechsler IQ (below 85) scored higher on Raven's. The gap was small. Kids with average or high Wechsler IQ showed no Raven boost.
The team warns that Raven's can give a false picture of strong intelligence when Wechsler IQ is low.
How this fits with other research
Papadopoulos et al. (2013) saw the same pattern with different tests. Leiter-R gave kids with autism IQ scores 21 points higher than Stanford-Binet. Both studies say: test choice changes the number you write down.
Green et al. (2020) looked deeper. They found that any nonverbal-over-verbal IQ split is only coin-flip accurate for spotting autism. Together these papers tell us to stop treating IQ profiles as diagnostic clues.
Saemundsen et al. (2003) showed ADI-R and CARS only agree two-thirds of the time. The theme is clear: different tools give different answers, so pick one path and stay consistent.
Why it matters
If you test a client with autism and the Wechsler score is under 85, do not celebrate a high Raven score as hidden genius. Use Wechsler for program planning. Add Raven only if you need a non-verbal backup. Always tell parents the number is tool-specific, not a fixed trait.
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02At a glance
03Original abstract
Owing to higher performance on the Raven's Progressive Matrices (RPM) than on the Wechsler Intelligence Scales (WIS), it has recently been argued that intelligence is underestimated in autism. This study examined RPM and WIS IQs in 48 individuals with autism, a mixed clinical (n = 28) and a neurotypical (n = 25) control group. Average RPM IQ was higher than WIS IQ only in the autism group, albeit to a much lesser degree than previously reported and only for individuals with WIS IQs <85. Consequently, and given the importance of reliable multidimensional IQ estimates in autism, the WIS are recommended as first choice IQ measure in high functioning individuals. Additional testing with the RPM might be required in the lower end of the spectrum.
Journal of autism and developmental disorders, 2009 · doi:10.1007/s10803-008-0667-2