Effects of Testing Accommodations and Item Modifications on Students' Performance: An Experimental Investigation of Test Accessibility Strategies
Beddow, Peter Albert
Test accessibility is defined as the extent to which a test and its constituent item set permits the test-taker to demonstrate his or her knowledge of the target construct. The proposed study used a 2 x 4 experimental design to test the effects of testing accommodations and item modifications on math test performance for two groups of students in grade 7: (a) students with IEPs (n = 103); and (b) students without IEPs (n = 329). Results indicated there was no effect of accommodations, but a moderate effect was observed for modifications, with an effect size nearly two times greater for students with IEPs compared to students with no IEPs. Correlational analyses of the relations between accessibility and item discrimination and item difficulty ranged from very small to moderate, with a moderate correlation between item difficulty and word count. The second phase of the study involved a student post-test survey to solicit perceptions of student access, opportunity to learn, cognitive ease, perceived difficulty, and perceived helpfulness of accommodations. For the total sample, students reported increased opportunity to learn the modified items, and reported the items were easier to comprehend, had lower cognitive demand, and students were more confident they responded correctly. Students with IEPs reported lower understanding, lower opportunity to learn the material, lower confidence, and reported the items were more difficult compared to students with no IEPs. Only 7% of students in the accommodated condition utilized any available accommodations; notwithstanding, self-report data indicated accommodations may have contributed to student self-efficacy. The contribution of the current study to an ongoing program of research on test accessibility, the refinement of accessibility theory, and large-scale assessment practices on alternate assessments of modified achievement standards is discussed.