Sensitivity and specificity of the Modified Checklist for Autism in Toddlers and the Social Communication Questionnaire in preschoolers suspected of having pervasive developmental disorders.

Richardson et al. (2008) looked at two quick parent checklists for autism: the M-CHAT for toddlers and the SCQ for preschoolers.

They wanted to know which cut-off scores catch the most kids who really have a pervasive developmental disorder without flagging too many who do not.

The team also checked if kids with lower IQ or daily-living scores needed different cut-offs.

Using the M-CHAT’s “any three items” rule and a lower SCQ cut-off gave the best mix of hits and correct passes.

Both tools worked better for preschoolers who also had lower cognitive or adaptive scores.

McLennan et al. (2008) did the same kind of tuning with the CSI-4 for older kids. They also trimmed item sets to keep accuracy high, showing short forms can work across ages.

Evers et al. (2020) compared two parent interviews and found only 75 % agreement; each missed different ASD signs. Their warning matches V et al.—no single tool catches every child, so cut-off choice matters.

Klin et al. (2005) showed poor overlap across three Asperger criteria sets. Together with V et al., the message is clear: the same child might pass one screener and fail another, so know your tool’s limits.

If you screen preschoolers, switch to the any-three-item M-CHAT rule and drop the SCQ cut-off. This simple change lowers missed cases, especially for kids who also show cognitive delays. Keep both checklists in your toolbox, but always pair them with clinical judgment and follow-up observation.