James E. Gilliam, Ph.D.
The normative sample for the GARS-2 consisted of a representative sample of 1,107 individuals with autism from the United States.
Reliability and Validity
Studies of the GARS-2's reliability and validity have confirmed that the test has strong psychometric characteristics. Coefficients of reliability (internal consistency and test-retest) for the subscales and entire test are all large to very large in magnitude. The validity of GARS-2 was demonstrated by confirming that: (a) the items of the subscales are representative of the characteristics of autism; (b) the subscales are strongly related to each other and to performance of other tests that screen for autism; and (c) GARS-2 standard scores discriminate persons with autism from persons with other severe behavioral disorders, such as persons with mental retardation and multi-disabilities.
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James E. Gilliam, Ph.D.
Dr. Gilliam received his Bachelors of Science degree from Eastern Michigan University, Masters degree from State University College at Buffalo, and his Ph.D. from the University of Michigan.
Dr. Gilliam has taught both at the University of Wisconsin-Whitewater and University of Texas at Austin. He has also, consulted with parents, universities, state agencies, and schools in several countries on issues related to children with disabilities.
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