Preliminary evidence of the structural validity and measurement invariance of the Quantitative-CHecklist for Autism in Toddler (Q-CHAT) on Italian unselected children

Abstract The Quantitative-CHecklist for Autism in Toddler (Q-CHAT) is a screening measure developed to detect the early signs of risk of Autism Spectrum Disorders (ASD) in children from 18-24 months of life. After a critical analysis of the validation studies that have analyzed the Q-CHAT, the present paper aimed at testing the structural validity of the questionnaire through Confirmatory Factor Analysis and determining whether it is invariant across gender. Furthermore, the study examined the internal validity of the measure, calculated the risk cut-off score, and evaluated gender differences. Five hundred forty-five questionnaires were completed by parents of children from unselected population (age M = 19.9 months;  sd = 1 month; age range = 18-21; 254 girls). Findings gave tolerable demonstration of the expected three-factor structure and measurement invariance across gender. Gender differences were also found as well as correlations among factors as a demonstration of internal validity. The risk cut-off of 43 was calculated based on the 95 th percentile of the distribution. In conclusion, the present study demonstrated preliminary findings of the validity of the Q-CHAT for Italian children. However, our findings suggested also that three items need to be reformulated because they show several psychometric problems and, after that, the factorial validity, measurement invariance, and internal validity should be re-tested. Further longitudinal studies are also needed to examine the validity criterion of the Q-CHAT to test the cut-off score.