Council of European Social Science Data ArchivesCESSDA is an umbrella organisation for social science data archives across Europe. Since the 1970s the members have worked together to improve access to data for researchers and students. CESSDA research and development projects and Expert Seminars enhance exchange of data and technologies among data organisations. Collectively the constituent CESSDA member organisations serve some 30,000+ social science and humanities researchers and students within the European Research Area each year, providing access to 25,000 data collections, delivering over 70,000 data collections per annum and acquiring a further 1,000 data collections each year. The CESSDA Catalogue enables users to locate datasets, as well as questions or variables within datasets, stored at CESSDA archives throughout Europe. Data collections include sociological surveys, election studies, longitudinal studies, opinion polls, and census data. Among the materials are international and European data such as the European Social Survey, the Eurobarometers, and the International Social Survey Programme.