Much policy evaluation is performed by nongovernmental actors. The communications media; university scholars and research centers; private research organizations such as the Brookings Institution, the Urban Institute, and the American Enterprise Institute; pressure groups; and public-interest organizations, such as Common Cause, the Audubon Society, and Ralph Nader and his “raiders” (a collection of public-interest activists) are examples; all make evaluations of public policies and programs that have greater or lesser effects on public officials.