In 1981/82 the first representative health survey (SOMIPOPS "Socio-medical indicators for the population of Switzerland") was conducted 1) to gain representative data on health status (perceived morbidity), use of health services, 2) to analyse the demand for health care, and 3) to develop reliable health and use indicators. In order to validate questionnaire and interview data (primary data sources), two additional (secondary sources) were used: income and wealth data for the whole of the original SOMIPOPS sample (N = 5,860), and health insurance records for 80% consenting members of the interviewed sample. The integration of different data sources on an individual level greatly enhances the analytic potential of health survey.