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Investigating the structure of the autism-spectrum quotient using Mokken scaling

Stewart, Mary E.; Allison, Carrie; Baron-Cohen, Simon; Watson, Roger


Mary E. Stewart

Carrie Allison

Simon Baron-Cohen


Traits similar to those shown in autism spectrum condition (ASC) are apparent in relatives of individuals with ASC, and in the general population without necessarily meeting diagnostic criteria for an ASC. We assess whether the Autism-Spectrum Quotient (AQ), a self-report measure, has hierarchical properties using Mokken scaling. Hierarchical scales allow the presence of a latent trait to be identified by discovering whether and how many specific items form an ordered array along it. Data were collected from 2 groups: (1) people with ASC (n = 449: 240 males, 209 females, M age 35.4 years, SD = 12.8) and (2) university students (n = 943: 465 males, 475 females, M age = 23.0 years, SD = 8.4). A single Mokken scale was obtained in the data from university students and 3 scales were obtained in the data from people with ASC. The scales all showed moderate Mokken scaling properties with the single scale obtained from university students showing weak invariant item ordering and 2 of the scales from people with ASC showing weak invariant item ordering. The AQ formed reliable Mokken scales. There was a large overlap between the scale from the university student sample and the sample with ASC, with the first scale, relating to social interaction, being almost identical. The present study confirms the utility of the AQ as a single instrument that can dimensionalize autistic traits in both university student and clinical samples of ASC, and confirms that items of the AQ are consistently ordered relative to one another.


Stewart, M. E., Allison, C., Baron-Cohen, S., & Watson, R. (2015). Investigating the structure of the autism-spectrum quotient using Mokken scaling. Psychological assessment, 27(2), 596-604.

Journal Article Type Article
Acceptance Date Jan 1, 2015
Publication Date 2015-05
Deposit Date Mar 31, 2015
Publicly Available Date Nov 23, 2017
Journal Psychological assessment
Print ISSN 1040-3590
Electronic ISSN 1040-3590
Publisher American Psychological Association
Peer Reviewed Peer Reviewed
Volume 27
Issue 2
Pages 596-604
Keywords Autism-spectrum condition, Item response theory, Mokken scaling, Autism-spectrum quotient
Public URL
Publisher URL
Additional Information Authors' accepted manuscript version of article first published online in Psychological assessment, 2015, v.27, no.2. This article may not exactly replicate the final version published in the APA journal. It is not the copy of record.


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