Accommodating students with disabilities in large-scale testing: A comparison of differential item functioning (DIF) identified across disability types

Many students with disabilities are provided accommodations to enable their participation in statewide assessment programs; however, there is concern that accommodations may invalidate test results. For test administrations to be considered valid for all student groups, there must be comparable measurement across groups. This can ensure that decisions based on test results are made in a fair manner for all students. In this study, measurement comparability for two groups of accommodated students with disabilities (i.e., accommodated students with physical disabilities and accommodated students with mental disabilities) was examined using differential item functioning (DIF) analysis, in which item-level characteristics of the test for these groups were systematically compared with those for a reference group of nonaccommodated students without disabilities. A relatively large number of DIF items were identified for both accommodated disability groups, suggesting that more attention to the testing needs of students with disabilities is warranted. Suggestions for future research are provided.