Validity and reliability of the Thai version of the Autism Treatment Evaluation Checklist: A two-phase diagnostic accuracy study

Background: This study aimed to evaluate the psychometric properties of the Thai version of the Autism Treatment Evaluation Checklist (Thai-ATEC); a tool which has been developed for Thai parents and caregivers who have children with autism spectrum disorder (ASD). Methods: : Approval for this study was first obtained from the appropriate Ethics committee and from the original Autism Treatment Evaluation Checklist (ATEC) developers. This was a two-phase study. Phase 1 consisted of the forward–backward translation of the ATEC and phase 2 included the testing of psychometric properties, i.e. the validity and reliability of the final draft of the tool. The validity of the tool was assessed by comparing Thai-ATEC scores of parents and caregivers of 160 children with ASD with the assessment of a child and adolescent psychiatrist using DSM-V criteria on the same group of children. The inter-rater reliability of the tool was tested using a two-way model of intra-class correlation coefficient (ICC) for two-parent/caregivers’ assessment of 50 children with ASD. Results: : The validity of the Thai-ATEC was moderate to high. A cut-off point of ≤38 scores was used to distinguish between children with ASD with mild symptoms and the rest of the children (sensitivity = 94%, specificity= 61.9%, and the area under ROC curve = 90%). A cut-off point of ≥68 scores was used to distinguish between children with ASD with a severe degree of symptoms and the rest (sensitivity = 94%, specificity = 62.8%, area under receiver operating characteristic curve = 85%). The inter-rater reliability was very strong (ICC = 0.97). Conclusions: : The Thai-ATEC has moderate to high validity and high reliability.