The project should represent the entire resident population of Switzerland aged 18 and above. In order to obtain representative data, the Swiss citizens invited to participate are selected in a strict random procedure distributed across the seven major regions of Switzerland, men and women, and three age groups (18–34 years, 35–64 years, 65+ years). The distribution ensures that the above-mentioned groups are approximately as well represented in the sample as in the Swiss resident population. A total of 13,860 people were invited to the first of the five survey waves; the net aim is to have at least 1,000 people left in the sample at the end of the fifth wave.
Since the survey is of national importance, the sample could be drawn from the sampling frame for surveys of persons and households (SRPH) of the Federal Statistical Office. The Verordnung über die Durchführung von statistischen Erhebungen des Bundes (vom 30. Juni 1993, Art. 13c, Abs.2, Bst. d.) regulates how the information from this register may be used.
Data collection is carried out by the Swiss Center of Expertise in the Social Sciences (FORS; https://forscenter.ch/) a total of five times every six months. Once the data are collected, they are checked and formatted and then made available in the Swiss database SWISSUbase (https://www.swissubase.ch/en/). The anonymized data are accessible to all interested parties.