Scientific background: RAADS-R
About this test
The RAADS-R was published in 2011 by Ritvo and colleagues as a revised version of the original RAADS, and is one of the most widely used screening instruments in research and clinical practice for autistic traits in adults. It's organized into four domains: social relatedness, circumscribed interests, language, and sensory-motor. The original study proposed a total-score threshold of 65 points, above which autistic traits are likely (non-autistic control group mean: approximately 21 points). Importantly: both lower and higher scores occur in both autistic and non-autistic people -- in particular, pronounced "masking" (see the CAT-Q) can lower the score. This test can therefore never replace a diagnosis, only provide an indication that further professional evaluation may be worthwhile.
Dimensions
Total Score
Sum across all 80 items (0–240 points). The original study proposes 65 points as a threshold.
Social Relatedness
Social reciprocity, interpersonal relationships, understanding social expectations and social cues.
Circumscribed Interests
Intense, focused interests, preference for sameness, difficulty with change, repetitive thoughts or behaviors.
Language
Pragmatic language features, literal interpretation, understanding metaphors and indirect meaning, small talk.
Sensory-Motor
Sensory sensitivities, sensory-seeking or reduced sensitivity, motor peculiarities, unusual speech tone and rhythm.
Sources & license
Ritvo, R. A., Ritvo, E. R., Guthrie, D., Ritvo, M. J., Hufnagel, D. H., McMahon, W., Tonge, B., Mataix-Cols, D., Jassi, A., Attwood, T., & Eloff, J. (2011). The Ritvo Autism Asperger Diagnostic Scale-Revised (RAADS-R): A scale to assist the diagnosis of autism spectrum disorder in adults: An international validation study. Journal of Autism and Developmental Disorders, 41(8), 1076–1089.
The questionnaire itself is copyrighted (© Riva Ariella Ritvo, Ph.D. and Edward Ritvo, M.D., 2007). The journal article containing it (Ritvo et al., 2011) is published via PMC under a Creative Commons Attribution-NonCommercial license, permitting non-commercial use with attribution -- the same basis on which numerous other freely accessible RAADS-R test sites operate. Item wording, subscale assignment, and the 17 reverse-scored items were verified directly against the official instrument as printed in the article's own appendix.
https://pmc.ncbi.nlm.nih.gov/articles/PMC3134766/