Since 2010 the FSO has a sample frame which forms the basis for high-quality person and household surveys. The sample frame uses data from cantonal and communal population registers, which are updated on a quarterly basis.
The samples are drawn randomly. In order to avoid individuals being selected too frequently, the FSO has introduced a system to ensure that the burden is evenly distributed across its surveys. If a household has already participated in an FSO survey, it will not be selected again for some time. This safeguard is not 100% effective, however, especially if a person changes household between two consecutive quarters. Special measures have been established to deal with such exceptions.
For which surveys can the sample frames be used?
The Federal Statistics Act limits the use of sample frames. Personal or household data necessary for the survey may only be passed on from the sample frame register for:
- Surveys that are part of the Confederation’s statistical multi-annual programme;
- Surveys ordered by the Federal Council in individual cases;
- Research projects that are carried out by administrative units of the central federal administration and Swiss research units and that are of national importance;
- Regular research projects that are funded by the Swiss National Science Foundation and considered to be research projects of national importance;
- International research projects that are co-funded by the Swiss National Science Foundation.
Important information on the availability of fixed-line telephone numbers in the sample frame
Until December 2023, the fixed-line telephone numbers came from the emergency call database managed by SWISSCOM. As this no longer exists in its old form, an interim solution was set up for 2024 and 2025, in which the largest telephone providers are used to procure the fixed numbers. From 2026, the sampling frame will no longer have any fixed-line telephone numbers.