The Harris Vault (a Nielsen company): Discover and explore over forty years of insight released by The Harris Poll®. Use the search function to uncover data spanning subject matter and industry – dating back to 1963.
Pew Research Center: An "independent opinion research group that studies attitudes toward press, politics and public policy issues." Contains summaries of results, comparisons of how attitudes change over time, copies of questionnaires, and descriptions of survey methodologies
PollingReport.com: "An independent, nonpartisan resource on trends in American public opinion."
Program For Public Consultation: The Program for Public Consultation (PPC) seeks to improve democratic governance by consulting the citizenry on the key public policy issues their government faces. PPC is part of the School of Public Policy at the University of Maryland.
World Public Opinion: International collaborative project whose aim is to give voice to public opinion around the world on international issues. Seeks to reveal the values and views of publics in specific nations around the world as well as global patterns of world public opinion.