The Institute for Defense Analyses (IDA) is an American non-profit corporation that administers three federally funded research and development centers (FFRDCs)- the Systems and Analyses Center (SAC), the Science and Technology Policy Institute (STPI), and the Center for Communications and Computing (C&C) - to assist the United States government in addressing national security issues, particularly those requiring scientific and technical expertise. It is headquartered in Alexandria, Virginia.