Validation of the Lebanese Childhood Autism Rating Scale-Second Edition-Standard Version

•We have compared children previously diagnosed with ASD with children diagnosed with ID for discriminant validity.•We have compared the rating of two independent examiners blind to the diagnosis for inter-rater reliability.•We have administered the CARS2-ST at one month interval to assess for the time stability of the rating.•We have compared the CARS scales results with the initial psychiatric diagnosis.

The purpose of this study is to validate the Childhood Autism Rating Scale-Second Edition-Standard Version (CARS2-ST) to the Lebanese population. The participants consisted of 109 children among which 90 had autism spectrum disorder (ASD) and 19 had intellectual disability (ID). Forward and backward translation was ensured before administration. The Wechsler Nonverbal Scale of Ability (WNV) was used to estimate the level of intellectual functioning. The Lebanese CARS2-ST was found to have a good reliability as measured by internal consistency (.95), inter-rater reliability (.99), and test–retest reliability (.89). It classified individuals as having ASD versus ID based on a cutoff score of 26 or higher for children younger than 13 years old and a cutoff score of 28.5 or higher for adolescents (≥13 years). A similar level of psychometric properties was found with the original CARS2-ST. Therefore, the Lebanese CARS2-ST is a useful tool for assessing for ASD among the Lebanese population.