Reliability of Autism-Tics, AD/HD, and other Comorbidities (A–TAC) Inventory in a Test-Retest Design
The Autism-Tics, AD/HD, and other Comorbidities (A–TAC) inventory is used in epidemiological research to assess neurodevelopmental problems and coexisting conditions. Although the A–TAC has been applied in various populations, data on retest reliability are limited. The objective of the present study was to present additional reliability data. The A–TAC was administered by lay assessors and was completed on two occasions by parents of 400 individual twins, with an average interval of 70 days between test sessions. Intra- and inter-rater reliability were analysed with intraclass correlations and Cohen's κ. A–TAC showed excellent test-retest intraclass correlations for both autism spectrum disorder and attention deficit hyperactivity disorder (each at .84). Most modules in the A–TAC had intra- and inter-rater reliability intraclass correlation coefficients of ≥ .60. Cohen's κ indicated acceptable reliability. The current study provides statistical evidence that the A–TAC yields good test-retest reliability in a population-based cohort of children.