Award Date


Degree Type


Degree Name

Doctor of Philosophy (PhD)


Educational Psychology & Higher Education

First Committee Member

Scott Loe

Second Committee Member

Tara Raines

Third Committee Member

Joe Crank

Fourth Committee Member

Shannon Smith

Number of Pages



Autism Spectrum Disorder (ASD) can be considered a serious developmental concern, which, complicated by its rising rate, creates a challenge for psychologists in properly and consistently diagnosing the disorder. Various types of assessments such as reporting measures, observation systems, and standardized assessments are currently used in the identification of ASD. Any one instrument typically examines multiple domains of functioning such as intellectual, neuropsychological (including adaptive, attention, sensory, motor, language, memory, executive functioning, academic, and social/emotional), and behavior (social and repetitive/restricted). Often, evaluators combine assessments that were not originally meant to detect ASD with those that were intended for that purpose. The most respected method of diagnosis of ASD at this time includes direct assessments as well as indirect in an attempt to maximize accuracy of clinical judgment. However, this method is not reflected in common identification practice for ASD; instead, many clinicians are relying on rating scales. Unfortunately, there are not a sufficient amount of studies examining the reliability of some of the available measures, especially with trainees. In particular, studies examining the sources of variance on the Autism Diagnostic Observation Schedule-Second Edition (ADOS-2) are limited in quantity and depth. The conceptual framework for this study will be Generalizability (G) Theory. This study is designed to expand upon currently available information regarding the interrater reliability of the ADOS-2 by using techniques available in G Theory in order to understand multiple sources of variance associated with the instrument, in particular with relation to coding by trainees.


ADOS-2; Assessment; G Theory; Rater; Reliability; Training


Educational Psychology

File Format


Degree Grantor

University of Nevada, Las Vegas




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