Public opinion may influence those creating policy statements, so here are some sites which monitor public opinions and provide polling data.
For additional statistical research, consult our Statistical and Empirical Legal Research Guide.
Public policy research and analysis is often the province of non-profit research organizations known as think tanks. The annual report of Global Go-To Think Tanks identifies and ranks both U.S. and international research centers by subject areas.
The Univeristy of North Carolina maintains a Customized Google Search engine that searches more than 300 think tanks for policy reports and white papers.
These sites link to Think Tank Directories -
Congressional Research Service - The CRS is a government "think tank" tasked with producing reports for members of Congress on all aspects of the government and current worldwide events. They do not make their reports public, but many of these reports are available through various websites and databases, such as ProQuest Congressional (Georgetown use only), Bloomberg Law, Federation of American Scientists and the U.S. Department of State.