Non-government organizations are also known as not-for-profits. They include think tanks, advocacy groups, and charities.

■ American Association for the Advancement of Science
■ Alliance for Health Care Reform
■ Amazon Conservation Team
■ American Enterprise Institute
■ Center for Democracy and Technology
■ Center for Strategic and International Studies
■ Climate Institute
■ Council on Competitiveness
■ Economic Policy Institute
■ Electronic Privacy Information Center
■ Environmental and Energy Study Institute
■ Federation of American Scientists
■ Institute of Medicine
■ National Academy of Sciences, including Physical Sciences and Transportation Research Board
■ National Capital Planning Commission
■ The Brookings Institution
■ Urban Institute
■ Woodrow Wilson Center for Scholars