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Factor Structure, Internal Consistency, and Screening Sensitivity of the GARS-2 in a Developmental Disabilities Sample


Affiliations
1 Department of Counseling, Educational Psychology, and Special Education, College of Education, Michigan State University, East Lansing, MI 48824-1034, United States
2 Department of Counseling, School and Educational Psychology, Graduate School of Education, University at Buffalo, The State University of New York, Buffalo, NY 14260-1000, United States
3 Institute for Autism Research, Canisius College, 2001 Main Street, Buffalo, NY 14208, United States
4 Summit Educational Resources, 150 Stahl Road, Getzville, NY 14068, United States
5 Psychology Department, College of Liberal Arts, Rochester Institute of Technology, Rochester, NY 14230, United States
 

The Gilliam Autism Rating Scale-Second Edition (GARS-2) is a widely used screening instrument that assists in the identification and diagnosis of autism. The purpose of this study was to examine the factor structure, internal consistency, and screening sensitivity of the GARS-2 using ratings from special education teaching staff for a sample of 240 individuals with autism or other significant developmental disabilities. Exploratory factor analysis yielded a correlated three-factor solution similar to that found in 2005 by Lecavalier for the original GARS. Though the three factors appeared to be reasonably consistent with the intended constructs of the three GARS-2 subscales, the analysis indicated that more than a third of the GARS-2 items were assigned to the wrong subscale. Internal consistency estimates met or exceeded standards for screening and were generally higher than those in previous studies. Screening sensitivity was .65 and specificity was .81 for the Autism Index using a cut score of 85. Based on these findings, recommendations are made for instrument revision.
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  • Factor Structure, Internal Consistency, and Screening Sensitivity of the GARS-2 in a Developmental Disabilities Sample

Abstract Views: 101  |  PDF Views: 22

Authors

Martin A. Volker
Department of Counseling, Educational Psychology, and Special Education, College of Education, Michigan State University, East Lansing, MI 48824-1034, United States
Elissa H. Dua
Department of Counseling, School and Educational Psychology, Graduate School of Education, University at Buffalo, The State University of New York, Buffalo, NY 14260-1000, United States
Christopher Lopata
Institute for Autism Research, Canisius College, 2001 Main Street, Buffalo, NY 14208, United States
Marcus L. Thomeer
Institute for Autism Research, Canisius College, 2001 Main Street, Buffalo, NY 14208, United States
Jennifer A. Toomey
Summit Educational Resources, 150 Stahl Road, Getzville, NY 14068, United States
Audrey M. Smerbeck
Psychology Department, College of Liberal Arts, Rochester Institute of Technology, Rochester, NY 14230, United States
Jonathan D. Rodgers
Institute for Autism Research, Canisius College, 2001 Main Street, Buffalo, NY 14208, United States
Joshua R. Popkin
Department of Counseling, School and Educational Psychology, Graduate School of Education, University at Buffalo, The State University of New York, Buffalo, NY 14260-1000, United States
Andrew T. Nelson
Summit Educational Resources, 150 Stahl Road, Getzville, NY 14068, United States
Gloria K. Lee
Department of Counseling, Educational Psychology, and Special Education, College of Education, Michigan State University, East Lansing, MI 48824-1034, United States

Abstract


The Gilliam Autism Rating Scale-Second Edition (GARS-2) is a widely used screening instrument that assists in the identification and diagnosis of autism. The purpose of this study was to examine the factor structure, internal consistency, and screening sensitivity of the GARS-2 using ratings from special education teaching staff for a sample of 240 individuals with autism or other significant developmental disabilities. Exploratory factor analysis yielded a correlated three-factor solution similar to that found in 2005 by Lecavalier for the original GARS. Though the three factors appeared to be reasonably consistent with the intended constructs of the three GARS-2 subscales, the analysis indicated that more than a third of the GARS-2 items were assigned to the wrong subscale. Internal consistency estimates met or exceeded standards for screening and were generally higher than those in previous studies. Screening sensitivity was .65 and specificity was .81 for the Autism Index using a cut score of 85. Based on these findings, recommendations are made for instrument revision.