The four key elements

The census system is based on a register survey that evaluates existing administrative data. To this end, the FSO uses cantonal and communal population registers, federal registers of persons and the Federal Register of Buildings and Dwellings. Information that is not contained in a register is collected with additional sample surveys: an annual structural survey of 200,000 people (cantons and cities can enlarge the sample for their area); thematic surveys of 10,000 or 40,000 persons (five themes, a different one each year); an Omnibus survey of 3,000 persons on topical issues.