Reliability and Validity of the Korean Version of the Quantitative Checklist for Autism in Toddlers: A Comparison Study Between the Clinical and Community Population

Objective This study aimed to evaluate the utility of the Korean version of the Quantitative Checklist for Autism in Toddlers (Q-CHAT) in hospital settings and to identify items sensitive for detecting autism spectrum disorder (ASD) trait. Methods The Q-CHAT was administered to a clinical sample of children presenting with developmental delays with a high probability of ASD in a hospital setting (n=37), as well as to typically developing community children (n=67), aged 12 to 54 months. Results The mean Q-CHAT total score in the hospital sample (42.0±13.6) was significantly higher than in the community sample (29.9±7.8), with maximized sensitivity and adequate specificity at 32.5 (sensitivity=0.811, specificity=0.687). The internal consistency of Q-CHAT was 0.764 for the overall sample and 0.825 for the hospital sample. Q-CHAT total scores and item scores in the hospital sample remained stable across age groups, indicating age-invariant properties. The hospital sample showed higher endorsement of less favorable development in social interaction and reciprocity items compared to community sample. No difference in the Q-CHAT item scores was present among age groups in the hospital samples. In the community samples, item scores, such as comprehending a child’s speech, using the hand of others as a tool, adapting to a change in routine, repeating the same action, and making unusual finger movements, decreased with the advance of age. Conclusion The Korean version of the Q-CHAT demonstrates good validity and reliability and is effective in discriminating autistic traits even in children older than 24 months. The items endorsed for hospital samples varied from community samples, implying itemspecific sensitivity for hospital samples.