Are autistic traits measured equivalently in individuals with and without an autism spectrum disorder? An invariance analysis of the Autism Spectrum Quotient Short Form.
The AQ-S keeps the same shape in both groups but the numbers lie—never compare raw scores across autistic and non-autistic clients.
01Research in Context
What this study did
The team asked if the 10-item Autism-Spectrum Quotient Short Form (AQ-S) works the same way for autistic and non-autistic people. They gave the scale to the adults with ASD and the adults without ASD. Then they ran math tests to see if a score of, say, 6 means the same thing in both groups.
What they found
The scale keeps the same structure: both groups answer the items in the same order of difficulty. But the numbers are off. A raw score of 6 in the ASD group does not equal a 6 in the non-ASD group. Only the pattern of answers is equal, not the level.
How this fits with other research
Wakabayashi et al. (2007) and Sonié et al. (2013) showed the full AQ separates autistic and typical people in Japan and France. Koegel et al. (2014) agrees the short form still separates groups, but adds a warning: do not compare raw scores directly.
Bora et al. (2017) used the same AQ-S in parents and found the Communication subscale drives the difference. This extends L’s point—once you know which subscale pushes the gap, you can interpret scores more carefully.
Huang et al. (2025) found a similar trap with the Social Responsiveness Scale in kids: higher scores in non-ASD children share genetics with ASD, so raw numbers can mislead. Both papers shout the same lesson—equal structure does not mean equal meaning.
Why it matters
If you give the AQ-S during intake, do not tell families that a score of 7 is “mild” for everyone. Use the scale to flag possible traits, then follow with interview and ADOS. When you write reports, keep ASD and non-ASD norms separate. This small step keeps your recommendations clear and fair.
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02At a glance
03Original abstract
It is common to administer measures of autistic traits to those without autism spectrum disorders (ASDs) with, for example, the aim of understanding autistic personality characteristics in non-autistic individuals. Little research has examined the extent to which measures of autistic traits actually measure the same traits in the same way across those with and without an ASD. We addressed this question using a multi-group confirmatory factor invariance analysis of the Autism Quotient Short Form (AQ-S: Hoekstra et al. in J Autism Dev Disord 41(5):589-596, 2011) across those with (n = 148) and without (n = 168) ASD. Metric variance (equality of factor loadings), but not scalar invariance (equality of thresholds), held suggesting that the AQ-S measures the same latent traits in both groups, but with a bias in the manner in which trait levels are estimated. We, therefore, argue that the AQ-S can be used to investigate possible causes and consequences of autistic traits in both groups separately, but caution is due when combining or comparing levels of autistic traits across the two groups.
Journal of autism and developmental disorders, 2014 · doi:10.1007/s10803-013-1851-6