Objective: To translate the Childhood Autism Rating Scale into Brazilian Portuguese and to determine the initial psychometric properties of the resulting version (CARS-BR).
Methods: The methodology used to produce an adequate version included translation, backtranslation and evaluation of semantic equivalence. In order to determine its psychometric properties (internal consistency, validity and reliability), the CARS-BR was administered to 60 consecutive patients with autism, aged between 3 and 17 years and seen at a university hospital.
Results: Internal consistency was high, with a Cronbach's alpha of 0.82. Convergent validity, in comparison with the Autistic Traits Assessment Scale, exhibited a Pearson's correlation coefficient of r = 0.89. When correlated with the Global Assessment of Functioning Scale in order to evaluate discriminant validity, the CARS-BR exhibited a Pearson's coefficient of r = -0.75. Test-retest reliability exhibited a kappa coefficient of 0.90.
Conclusion: These results suggest that the CARS-BR is a valid and reliable instrument for evaluating autism severity in Brazil.