The aim of this study was to examine the psychometric properties of an adapted version of the Quantitative Checklist for Autism in Toddlers (Q-CHAT), an early screening tool that quantifies autistic traits dimensionally, in a community sample of Chilean children aged 18-24 months. An intentional non-probabilistic sampling was used. All primary caregivers of children aged 18-24 months who attended health check-up at four primary care clinics in Chile's Araucanía region during the study period were invited to participate. One hundred and eighty-eight toddlers were screened. Evidence of construct validity was determined through Exploratory Factor Analysis (EFA), evidence of convergent validity with the Modified Checklist for Autism in Toddlers, Revised with Follow-Up (M-CHAT-R/F), and evidence of reliability through internal consistency and test-retest. The EFA showed a two-factor structure, which explained 42.2 % of the variance: “Restrictive and Repetitive Patterns” (factor 1), and “Communication and Social Interaction” (factor 2). The total Q-CHAT scores correlated positively and significantly with the total M-CHAT-R/F scores (r=0.59, p<0.01) with a large effect size. Internal consistency was acceptable for the scale in general (α=0.74), acceptable for factor 1 (α = 0.76) and good (α=0.85) for factor 2. Regarding test-retest stability, the intraclass correlation coefficient was good (ICC=0.86, p<0.001). In terms of the factor structure evidenced by the EFA, the two factors are theoretically consistent with the current diagnostic criteria of the DSM-5. The evidence of validity and reliability of Q-CHAT is encouraging when considering its use as an early detection tool in Chile.
The psychometric properties of the Quantitative-Checklist for Autism in Toddlers (Q-CHAT) as a measure of autistic traits in a community sample of Singaporean infants and toddlers
