This report reviews the current literature (mostly since 1993) on testing accommodations for students with disabilities, with an emphasis on studies examining the effects of testing accommodations on the technical integrity of assessment measures. The report notes a continuing lack of empirical research on testing accommodations, but evidence of changes in policy (especially enactment of the Americans with Disabilities Act and implementation of the National Education Goals) suggests that accommodations will receive more direct attention. The recent federal funding of projects to examine issues related to assessment for students with disabilities is also noted, as is the increasing number of journal articles, books, and professional documents about testing and accommodations. The report is organized into five sections: (1) a brief description of the methodology used to conduct the literature review; (2) empirical studies of testing accommodations; (3) legal considerations related to testing accommodations; (4) teacher and student perceptions of testing accommodations and modifications; and (5) conceptual issues. Appended are a review of early studies in testing accommodations conducted by the American College Testing Program and the Educational Testing Service and a listing of relevant research projects currently supported by the U.S. Department of Education. (Contains 39 references.) (DB)