Psychometric properties of the Ritvo Autism and Asperger Diagnostic Scale: Revised (RAADS-R) in the Persian language for Iranian adults

ObjectivesAutism Spectrum Disorder (ASD) typically manifests in childhood and continues into adulthood. There are very few validated scales for screening ASD during adulthood. This study aimed to measure the psychometric properties of the Ritvo Autism and Asperger Diagnostic Scale: Revised (RAADS-R) among Iranian adults.MethodsA sample of 88 autistic individuals and 144 healthy controls were recruited. To establish concurrent validity, the scores on the questionnaire were correlated with the Autism Quotient (AQ) questionnaire. The construct validity of the RAADS-R was evaluated by examining its correlation with Social Responsiveness Scale (SRS), CGI (Clinical Global Impression) rating scale, and Stanford-Binet Intelligence Scale. We measured internal consistency using Cronbach's Alpha, Spearman-Brown, and Guttman Split-Half Coefficients, and test-retest reliability.ResultsInternal consistency was obtained at 0.91 by Cronbach's Alpha. The test-retest reliability of the RAADS-R was found to be excellent, with a coefficient of 0.91. A significant relationship between RAADS-R and AQ (r: 0.47), SRS (r: 0.86) and CGI (r: 0.94) was observed proving concurrent and construct validity. A Score of 67 showed optimal sensitivity (0.98) and specificity (0.99) in discriminating between normal and clinical populations.ConclusionsOur findings showed favorability of Persian version of RAADS-R in indices of reliability and validity.