Factor Structure, Internal Consistency, and Screening Sensitivity of the GARS-2 in a Developmental Disabilities
Martin A Volker1, Elissa H Dua2, Christopher Lopata3
1Department of Counseling, Educational Psychology, and Special Education, College of Education, Michigan State University, East Lansing, MI 48824-1034, USA.
Autism Research and Treatment
|March 17, 2016
Summary
The Gilliam Autism Rating Scale-Second Edition (GARS-2) shows good internal consistency for autism screening. However, revisions are recommended due to item placement issues impacting its factor structure.
Area of Science:
- Psychometrics
- Developmental Psychology
- Special Education
Background:
- The Gilliam Autism Rating Scale-Second Edition (GARS-2) is a key tool for autism identification.
- Previous research has established its utility, but its psychometric properties require ongoing validation.
Purpose of the Study:
- To evaluate the factor structure, internal consistency, and screening accuracy of the GARS-2.
- To provide recommendations for potential GARS-2 revisions based on empirical findings.
Main Methods:
- Exploratory factor analysis was conducted on GARS-2 ratings from 240 individuals with autism or developmental disabilities.
- Internal consistency and screening sensitivity/specificity were calculated for the Autism Index.
Main Results:
- A three-factor solution was identified, aligning with GARS-2 constructs but with over a third of items misassigned.
- Internal consistency estimates met or exceeded screening standards.
- The Autism Index demonstrated a sensitivity of .65 and specificity of .81 at a cut score of 85.
Conclusions:
- The GARS-2 exhibits strong internal consistency and acceptable screening performance.
- Findings suggest the need for GARS-2 revision to improve item alignment with subscale constructs.
- Further research is warranted to refine the GARS-2 for more accurate autism diagnosis.
