Stone, E., Cook, L., Cahalan Laitusis, C., & Cline, F. (2010). Using differential item functioning to investigate the impact of testing accommodations on an English-language arts assessment for students who are blind or visually impaired . Applied Measurement in Education , 23 (2), 132–152. https://doi.org/10.1080/08957341003673773

Students were tested with either a large print or braille form.

Grades 4 and 8 students without disabilities, and students who are blind or visually impaired from an unidentified U.S. state, were participants. An extant data set including state test scores from grade 4 (n=30,225) and grade 8 (n=30,069) students without disabilities were analyzed, as were scores from grade 4 (n=105) and grade 8 (n=74) students with blindness or visual impairments.

An extant data set of one state's performance scores from a large-scale English-language arts (ELA) test.

Using the Mantel-Haenszel method, only one item at each grade was flagged as displaying large differential item functioning (DIF), in each case favoring students without disabilities. Additional items were flagged as exhibiting intermediate DIF, with some items found to favor each group. A priori hypothesis coding and attempts to predict the effects of large print or braille accommodations on DIF were not found to have a relationship with the actual flagging of items, although some a posteriori explanations could be made. The results are seen as supporting the accessibility and validity of the current test for students who are blind or visually impaired while also identifying areas for improvement consisting mainly of attention to formatting and consistency.