Date of Award


Degree Type


First Advisor

MaryAnn Romski

Second Advisor

Laura Dilly

Third Advisor

Robin Morris

Fourth Advisor

Rose Sevcik

Fifth Advisor

Erin Tully


Autism is a complex and heterogenous neurodevelopmental disorder characterized by impairments in social communication skills and the presence of restricted and repetitive behaviors or interests (RRB’s). While prevalence rates of autism have increased rapidly in the past decade, it remains a challenging disorder to measure and diagnose. Cognitive functioning can influence the presentation of autism symptoms and children’s performances on standardized autism measures like the Autism Diagnostic Observation Schedule, Second Edition (ADOS-2), which contributes to misdiagnosis. This study examined retrospective chart review data from 188 children referred for clinical autism evaluations who were administered Module 3 of the ADOS-2. Findings demonstrated the superior fit and utility of a bifactor model to characterize autism symptomatology on the ADOS-2, Module 3. Results revealed non-significant effects of cognitive functioning on ADOS-2 performance and confirmed the measure’s ability to assess autism overall. However, nuanced RRB’s were not fully captured by the ADOS-2 in this sample of children. Regarding clinical diagnosis, a general autism trait measured by the ADOS-2 had the largest influence on diagnostic outcomes, and cognitive functioning had little influence. Lastly, this study revealed several small differences in the magnitude and direction of relations between verbal cognition and autism symptomatology in Black compared to White children.


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Available for download on Wednesday, August 23, 2023