Publications & Resources
Examining Differential Item Functioning in Reading Assessments for Students with Disabilities
Jamal Abedi, Seth Leon, and Jenny C. Kao
This study examines performance differences between students with disabilities and students without disabilities using differential item functioning (DIF) analyses in a high-stakes reading assessment. Results indicated that for Grade 9, many items exhibited DIF. Items that exhibited DIF were more likely to be located in the second half of the assessment subscales. After accounting for reading ability using a proxy score from items on the first half of the subscales, students with disabilities consistently underperformed on items located in the second half relative to the items located in the first half, as compared with students without disabilities. These results were seen in Grade 9 for data from two different states, but not for Grade 3.
This study has several limitations. There was no access to information regarding the testing accommodations that students with disabilities might have received, and no access to the type of disabilities. Results of this study can shed light on potential factors affecting the accessibility of reading assessments for students with disabilities, in an ultimate effort to provide assessment tools that are conceptually and psychometrically sound for all students. A companion report is available examining differential distractor functioning for students with disabilities.
Abedi, J., Leon, S., & Kao, J. C. (2008). Examining differential item functioning in reading assessments for students with disabilities (CRESST Report 744). Los Angeles: University of California, Los Angeles, National Center for Research on Evaluation, Standards, and Student Testing (CRESST).