Date of Award


Degree Type


Degree Name

Master of Arts (MA)



First Advisor

Diana Robins

Second Advisor

Lauren Adamson

Third Advisor

Erin Tully

Fourth Advisor

Lisa Wiggins


The Positive Predictive Value (PPV) of the Modified Checklist for Autism in Toddlers (M-CHAT), a parent report autism screening tool, is higher for males than for females (Ludwig et al., IMFAR 2011). Given the long waitlists and high costs for ASD evaluations, there is a need to reduce the number of false positive females on the M-CHAT. The current study examined the sex specific clinical profiles of toddlers who received an ASD evaluation based on M-CHAT screen positive status in order to explore potential differences that may contribute to the differential PPV of the M-CHAT in boys and girls. The sample included 250 males and 106 females (mean age=25.3 months, SD=4.6) who were evaluated based on screen positive status on the M-CHAT. Although children with ASD demonstrated greater ASD symptoms, lower IQ and weaker language and motor skills, minimal sex differences were discovered.