The Roper Center for Public Opinion Research is one of the world's leading archives of social science data, specializing in data from surveys of public opinion back to the 1930s. The archive provides access to their resources through two principle resources: iPOLL allows you to search a database of more then 400,000 questions from surveys. Response frequencies are provided for each question and for some questions simple cross-tabulations are available [these are designated with a Roper Explorer Icon]. Roper Express provides searching capability and access to the code books and raw data files of Over 10,000 US and 8,000 International polls. Note: there are many questions in iPOLL that do not have corresponding data files in Roper Express.