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 i n 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 accommodatio ns on the scores of students with disabilities on challenging mathematics a nd science performance assessment tasks. The major objectives of the invest igation were to (a) document the testing accommodations educators actually use when assessing students with performance assessment tasks, and (b) exam ine the effect that accommodations have on test results. Both descriptive a nd experimental methods were used to analyze data. Individual cases of stud ents with disabilities represent the strength and uniqueness of this resear ch. The predominant research design in this investigation is a between-seri es design featuring an alternating treatment design element. This data coll ection and analysis plan guided our work with 100 fourth graders, of whom 4 1 were students with disabilities. The results of the investigation indicat ed that slightly more than 75% of the testing accommodation packages that w ere suggested by students' individual education plan teams had a moderate t o large effect on their test scores. It was also found that testing accommo dations, to a lesser extent, had a positive effect on the test scores of st udents without disabilities. For a small percentage of students, the effect s of suggested accommodations were not positive. These results are discusse d in terms of validity and accountability issues for large-scale assessment programs. (C) 2001 Society for the Study of School Psychology. Published b y Elsevier Science Ltd.