This report reviews existing research on the effects of high stakes tests on students, particularly students with disabilities. The review focuses on potential effects on the curriculum, student learning, attitudes and school climate, and the costs versus benefits of high stakes testing of students with disabilities. Results indicate that research results on high stakes testing are inconclusive and vary with the type of research questions asked and the types of tests examined. The evidence suggests that teachers change the curriculum based on the tests and concentrate time and effort teaching to test content and format. The effects on student learning are largely unknown, but the evidence does suggest that increasing test scores in themselves do not serve as evidence that students are learning more. High stakes testing seems to have a negative effect on the attitudes and workloads of teachers, but little is known about the effects on students. States still do not take into account the full costs of high stakes testing programs, and claims that testing alone can cause major educational improvement have not been proven. Recommendations for future research are provided. An appendix summarizes the literature reviewed for the report. (Contains 46 references.) (CR)