Roper Center Public Opinion Archives The Roper Center is a public opinion archive that preserves the data from polls conducted by many leading survey organizations. Most of the data are from the United States, but over 50 nations are represented. The iPOLL databank offers access to nearly half a million survey questions and answers asked in the U.S. by more than 150 survey organizations. Direct links are given to study documentation and datasets. Date coverage: 1930s – present.