Experimental analysis of the effects of testing accommodations on the scores of students with and without disabilities

As a result of changes to the Individuals with Disabilities Education Act (IDEA) in 1997, ail students with disabilities are expected to participate in state and district assessment systems for accountability. To fulfill this participation mandate, individualized testing accommodations are permitted. This investigation focused on the use and effects of testing accommodations on the scores of students with disabilities on challenging mathematics and science performance assessment tasks. The major objectives of the investigation were to (a) document the testing accommodations educators actually use when assessing students with performance assessment tasks, and (b) examine the effect that accommodations have on test results. Both descriptive and experimental methods were used to analyze data. Individual cases of students with disabilities represent the strength and uniqueness of this research. The predominant research design in this investigation is a between-series design featuring an alternating treatment design element. This data collection and analysis plan guided our work with 100 fourth graders, of whom 41 were students with disabilities. The results of the investigation indicated that slightly more than 75% of the testing accommodation packages that were suggested by students' individual education plan teams had a moderate to large effect on their test scores. It was also found that testing accommodations, to a lesser extent, had a positive effect on the test scores of students without disabilities. For a small percentage of students, the effects of suggested accommodations were not positive. These results are discussed in terms of validity and accountability issues for large-scale assessment programs. (C) 2001 Society for the Study of School Psychology. Published by Elsevier Science Ltd.