Sociology

The Roper Center for Public Opinion Research, located at Cornell University, is one of the world’s leading archives of social science data, specializing in data from public opinion surveys.

"Pew Research Center is a nonpartisan fact tank that informs the public about the issues, attitudes and trends shaping the world. It conducts public opinion polling, demographic research, media content analysis and other empirical social science research. Pew Research Center does not take policy positions. It is a subsidiary of The Pew Charitable Trusts."

Nielsen is a for-profit company, but articles and press releases, as well as selected reports are available free from the website. Content focuses on consumer behavior, especially in regard to shopping, entertainment and media.