A comprehensive psychometric analysis of autism‐spectrum quotient factor models using two large samples: Model recommendations and the influence of divergent traits on total‐scale scores

The Autism‐Spectrum Quotient (AQ) is a psychometric scale that is commonly used to assess autistic‐like traits and behaviors expressed by neurotypical individuals. A potential strength of the AQ is that it provides subscale scores that are specific to certain dimensions associated with autism such as social difficulty and restricted interests. However, multiple psychometric evaluations of the AQ have led to substantial disagreement as to how many factors exist in the scale, and how these factors are defined. These challenges have been exacerbated by limitations in study designs, such as insufficient sample sizes as well as a reliance on Pearson, rather than polychoric, correlations. In addition, several proposed models of the AQ suggest that some factors are uncorrelated, or negatively correlated, which has ramifications for whether total‐scale scores are meaningfully interpretable—an issue not raised by previous work. The aims of the current study were to provide: (a) guidance as to which models of the AQ are viable for research purposes, and (b) evidence as to whether total‐scale scores are adequately interpretable for research purposes. We conducted a comprehensive series of confirmatory factor analyses on 11 competing AQ models using two large samples drawn from an undergraduate population (n = 1,702) and the general population (n = 1,280). Psychometric evidence largely supported using the three‐factor model described by Russell‐Smith et al. [Personality and Individual Differences 51(2), 128–132 (2011)], but did not support the use of total‐scale scores. We recommend that researchers consider using AQ subscale scores instead of total‐scale scores.