Second, in our view, research that examines the effects of accommodations in terms of gains or losses associated with taking the test with or without accommodations is not a means of evaluating the validity of inferences based on accommodated scores. Such research does not provide evidence that scores for students who take a test under standard conditions are comparable to scores for students who take a test under accommodated conditions or that similar interpretations can be based on results obtained under different conditions.
Thus the committee concludes that:
CONCLUSION 5-1: Most of the existing research demonstrates that accommodations do affect test scores but that the nature of the effects varies by individual.
CONCLUSION 5-2: For the most part, existing research has investigated the effects of accommodations on test performance but is not informative about the validity of inferences based on scores from accommodated administrations. That is, existing research does not provide information about the extent to which inferences based on scores obtained from accommodated administrations are comparable to inferences based on scores obtained from unaccommodated administrations. Furthermore, the research does not provide definitive evidence about which accommodations would produce the most valid estimates of performance.
Based on these findings, the committee believes that a program of research is needed that would systematically investigate the extent to which scores obtained from accommodated and unaccommodated test administrations are comparable and support similar kinds of inferences about the performance of students with disabilities and English language learners on NAEP and other large-scale assessments.
RECOMMENDATION 5-1: Research should be conducted that focuses on the validation of inferences based on accommodated assessments of students with disabilities and English language learners. Further research should be guided by a conceptual argument about the way accommodations are intended to function and the inferences the test results are intended to support. This research should include a variety of approaches and types of evidence, such as analyses of test content, test-takers’ cognitive processes, and criterionrelated evidence, and other studies deemed appropriate.
Available research has not adequately investigated the extent to which different accommodations for students with disabilities and English language learners may