Objective: To replicate the factor structure and predictive validity of revised Autism Diagnostic Observation Schedule algorithms in an independent dataset (N = 1,282).

Method: Algorithm revisions were replicated using data from children ages 18 months to 16 years collected at 11 North American sites participating in the Collaborative Programs for Excellence in Autism and the Studies to Advance Autism Research and Treatment.

Results: Sensitivities and specificities approximated or exceeded those of the old algorithms except for young children with phrase speech and a clinical diagnosis of pervasive developmental disorders not otherwise specified.

Conclusions: Revised algorithms increase comparability between modules and improve the predictive validity of the Autism Diagnostic Observation Schedule for autism cases compared to the original algorithms.