To examine the classification rates and screening properties, including sensitivity and specificity, of the web-based Modified Checklist for Autism in Toddler, Revised with Follow-Up (M-CHAT-R/F) compared with paper–phone administration, and to determine the extent to which electronic M-CHAT-R/F streamlines screening, increases screening fidelity, increases diagnostic evaluation participation, and decreases waiting time from screening to evaluation compared with paper–phone modality.

Primary-care practices in urban and suburban settings administered either the web-based or paper-phone M-CHAT-R/F using a prospective nonrandomized control design. Toddlers (n = 17 900) were screened between 2009 and 2016 at routine well-child check-ups. Toddlers who screened at risk on the M-CHAT-R/F were invited to complete diagnostic evaluations; 176 children were diagnosed with autism. The χ², Fisher exact, and t-tests, as well as regression and screening properties, were used to compare outcome distributions, screening properties, and implementation by modality.

Classification rates of the initial M-CHAT-R into low, medium, and high risk were significantly different across modalities with very small effect sizes. Sensitivity and specificity were high across both modalities. For children in the medium-risk range, the web-based modality had a greater rate of predicting risk for autism after Follow-Up compared with the paper–phone modality, and the web eliminated delay between initial screen and Follow-Up. The web-based modality showed increased screening fidelity, no data loss, and similar rates of evaluation attendance and time to evaluation from Follow-Up administration.

The web-based M-CHAT-R/F is a valid tool for universal autism screening. Systems-level decisions should balance the increased feasibility of the electronic administration with the increase in Follow-Up accuracy provided by skilled clinician interview.