A two-year follow-up on risk status identified by the checklist for autism in toddlers.

We examined the characteristics of children at 4 to 5 years of age who were correctly and incorrectly classified as "at risk" for an autism spectrum diagnosis using the Checklist for Autism in Toddlers (CHAT) at age 2 to 3 years. Information is provided on the stability of risk/disorder status over a 2-year period of early development. Participants were 19 children with autism and 11 children with other developmental disabilities who had all been administered the CHAT between 2 and 3 years of age (Time 1) and received diagnostic and developmental re-evaluations between 4 and 6 years of age (Time 2). The risk status of children was discussed based on the original CHAT authors' criteria for risk of autism and the Denver modification for risk. High levels of stability in risk/diagnostic status from Time 1 assessments to Time 2 assessments were noted. Specifically, the original CHAT criteria for medium to high risk of autism applied at Time 1 predicted Time 2 diagnostic classification for 83% of the sample, and the Denver modification of the CHAT risk criteria predicted Time 2 diagnostic classification for 93% of the sample. Implications of the findings are discussed as they relate to early screening and identification of autism spectrum disorders.