McKevitt, B., Marquart, A., Schulte, A. G., Elliott, S. N., & Kratochwill, T. R. (2000, April). Understanding the effects of testing accommodations: A single case approach . Annual meeting of the National Association of School Psychologists (NASP), New Orleans, LA, United States.

All students with disabilities completed half of the tasks with accommodations recommended by teachers. The other half of the tasks were completed independently. Students without disabilities were randomly assigned to one of three test conditions: 1) no accommodations, 2) three common accommodations (reading and paraphrasing directions [read-aloud], providing verbal encouragement, and giving extra time [extended-time]) provided on half of the math and science tasks, 3) accommodations recommended by the students' teachers provided on half of the math and science tasks. The most common accommodations used by students with disabilities were verbal encouragement of effort, read directions to student (read-aloud directions), simplify language in directions, reread subtask directions, have student reread directions to the teacher, read test questions and content to student (read-aloud), and re-state questions with more appropriate vocabulary.

143 fourth-grade students (58 with a diagnosed disability under Wisconsin eligibility criteria receiving special education; 41% of sample) from Wisconsin (U.S.) were included. 46.4% were female, 53.6% were male. The ethnic breakdown was as follows: 7.2% African-American, 1.8% Multi-ethnic, 89.6% White, .9% Hispanic, .5% Native American. Students with a variety of disabilities were included.

Science and math performance assessments were developed as part of the Wisconsin Student Assessment System project in 1993-1995.

Accommodations had a medium to large positive effect on 81% of students with disabilities and 51% of students without disabilities. Small to zero effects were found for 5% of students with disabilities, and 41% of students without disabilities. Accommodations had a negative effect on scores of 14% of students with disabilities and 7.8% of students without disabilities. There was only a slight increase in the scores of students without disabilities who received individualized accommodations compared to those who received the standard package. The resulting effect size when comparing accommodated to non-accommodated scores was .94 for students with disabilities, .44 for students without disabilities receiving the standard package, and .55 for students without disabilities receiving the teacher-recommended accommodations.(see also Elliott et al., 1999; McKevitt et al., 1999; McKevitt, 2000; Elliott et al. 2001)