Brief Report: Checklist for Autism Spectrum Disorder: Most Discriminating Items for Diagnosing Autism.

The team looked at the 30-item Checklist for Autism Spectrum Disorder (CASD). They asked which six items give the same yes-or-no answer as the full list.

They tested the mini list on four separate groups of children already thought to have autism. The kids ranged from preschool through high-school age.

The six-item short form matched the full diagnosis 98 to 100 percent of the time in every group. That is the same accuracy as the 30-item parent interview.

The six questions cover social, communication, and ritual traits that best separate autism from other delays.

Mandell et al. (2016) and Grodberg et al. (2012) beat them to the punch. Those papers trimmed an eight-item Autism Mental Status Exam for toddlers and still hit 94 percent sensitivity. The new six-item CASD now does the same job for a wider age range and uses parent report instead of clinician observation.

Larsen et al. (2020) seems to disagree. Their short teacher checklist failed to spot autism in 12- to 24-month-olds at day care. The difference is age and informant: infants show fewer clear signs, and teachers see less of the child’s full day. Parent report in the CASD study captured richer, home-based examples, so the tools are not truly in conflict.

Galdino et al. (2020) later showed the eight-item AMSE also works in Brazilian Portuguese. Together these studies build a family of ultra-brief screeners that stay accurate across cultures and languages.

You can now screen for autism in under five minutes with six parent questions. Use the short CASD while families wait for a full ADOS slot, or re-screen annually to catch missed cases. The tool travels well—no toys, no clinic space, no extra staff—so school districts and telehealth teams can adopt it tomorrow.