The Special Education Research and Development Centers of the Institute of Education Sciences contribute to the solution of significant special education and early intervention problems in the United States by engaging in research, development, evaluation, and national leadership activities aimed at improving child outcomes through enhancements in the special education and early intervention systems. Each Center conducts a focused program of research in a specific topic area. Each Center works cooperatively with the Institute to provide relatively rapid research and scholarship on supplemental questions that emerge within the Center's topic area and that are not being addressed adequately elsewhere. In addition, each Center provides national leadership in advancing evidence-based practice and policy within its topic area. Currently, there are two National R&D Centers.