Lindstrom, W., Lindstrom, J. H., Barefield, T. T., Slaughter, M. H., & Benson, E. W. (2021). Examination of extended time use among postsecondary students with non-apparent disabilities . Journal of Postsecondary Education and Disability , 34 (4), 297–309. https://www.ahead.org/professional-resources/publications/jped

[no doi reported]; also located on ERIC online https://eric.ed.gov/?id=EJ1342740

The study examined the use of the 150% (also termed "time-and-a-half") extended time accommodation.

A sample of 2,227 undergraduate course tests taken by postsecondary students with learning disabilities, attention-deficit/hyperactivity disorder (ADHD), and psychological disorders who came to a university disability services office during spring semester of 2018 and who used the 150% extended time on tests and midterm exams were analyzed. More than one test was analyzed for some students.

The amount of time used by students when taking the tests and midterm exams included in the sample were analyzed. The amount of time used was examined by disability type and year in school using two-way analysis of variance (ANOVA) and post-hoc comparisons. Descriptive statistics were calculated.

Most students did not use the full amount of time allowed. No relationship was found between disability type and amount of time used. In general, students with multiple disabilities did not use more time than those with one identified disability.