Article 14a of the Federal Statistics Act (FStatA; SR 431.01) provides the legal basis for the linkage of data for statistical purposes.
The linkage of data (for statistical purposes) using data from the Federal Register of Buildings and Dwellings (RBD) and the Business and Enterprise Register (BER), is explicitly provided for in the Federal Act on the Harmonisation of the Register of Residents and of other Official Registers of Persons (RHA; SR 431.02). When linking data, particular attention must be paid to data protection. For this purpose, the Federal Act on Data Protection (FADP; SR 235.1) and the corresponding Federal Ordinance on Data Protection (OFADP; SR 235.11) provide an important legal basis, in particular Art. 11a and 22 of the FADP and Art. 11. and 25 of the OFADP.
The provisions for implementation of Art. 14a of FStatA are to be found:
- in the Ordinance on the Conduct of Federal Statistical Surveys, (Statistical Surveys Ordinance, SR 431.012.1), and notably in Art. 8a and section 2a data links, Art. 13h and 14 (clarifications may be found in the accompanying "Notes concerning amendments to the ordinance"; see Annex 7), as well as
- in the FDHA Ordinance on the linking of statistical information (Data Linkage Ordinance; SR 431.012.13).
Links are one of the main instruments of public statistics for a transition from survey-oriented to output-oriented statistics production.
The linking of data concerns the linking of individual data from different sources. The linkage of individual data from different sources refers to natural persons and legal entities or other observation units such as households, businesses, buildings, etc. The data sources can be existing data collections (registers or administrative data), direct surveys (interviews), observations or measurements.
The linking of data involves the collection and evaluation of output-oriented, integrated information system data from such different sources as registers, administrative data and surveys. As well as improved (multiple) use of data, such a system has an additional advantage in that new statistics can be based on existing data. This makes it possible to better serve the growing information needs of users from business, society and politics, administration and research.
A data link usually requires two different data sources (data on the same person, the same unit or the same subject). The same registers, surveys or panels, evaluated or carried out at different periods are viewed as different data sources (e.g. a survey every three years on environmental protection or R&D spending). This is not the case however with short-term surveys (up to a year at most) which are conceived as a functional unit (notably to monitor changes or show developments).
The interconnection of data with nomenclatures or the insertion of geo-coordinates does not count as linking, as these merely serve to indicate or to structure information that is already available.
The Federal Statistics Act and the Federal Act on Data Protection, as well as the Code of Practice (COP), the Charter of Swiss Official Statistics and the instructions of the Federal Administration concerning information security are equally valid in the context of the FSO. Further measures are planned with regard to links, notably concerning the transparency of linkage activities, such processes as data protection and the use of pseudonyms for individual data.
In addition to the legal bases, the FSO has a processing policy that covers basic principles (guidelines for data linkage) as well as organisational and technical provisions.
The FSO recognises the following linkage categories:
- Systematic links for the production of statistics
Links for the generation of official statistics: the FSO carries out systematic linking for the production of statistics (input links). In the Annex to the Ordinance on the Conduct of Federal Statistical Surveys, (Statistical Surveys Ordinance, SR 431.012.1), any statistic can be taken for which a link has been provided.
- Longitudinal linkage
Longitudinal linkage refers to the bringing together of variables of the same units from surveys or administrative data sources at different times (e.g. annual or multi-annual surveys) so as to obtain information about changes or process flow. Links concern only individual data – time series of aggregated units are not affected in the framework of the linkage (e.g. price indices, production and employment trends, etc.).
- Linkages for statistical analysis
Linkages (output linkages) for statistical analysis serve to ensure conformity with legal requirements as well as to promote transparency with regard to documented applications. This applies equally to internal FSO applications as well as external applications. These linkages do not serve for production, but rather for statistical analysis.