The new census can only exploit its full potential if it takes the form of a well-functioning integrated system. In order to create an integrated system, integration components are needed which will bring together surveys based on different data sources. Collectively used basic populations, the new AHV/AVS number, the Buildings and Dwellings Identifier (EGID/EWID) and key variables fulfil this function.
The basis of the integrated system is the collectively used basic populations which are uniformly defined and harmonised. They determine the framework of the persons, household and building and dwelling statistics using the statistical units that are being monitored. These are:
- The permanent resident population: This basic population comprises all Swiss citizens registered in Switzerland with a main place of residence as well as all foreign nationals with a residence permit for at least 12 months or having resided in Switzerland for at least 12 months;
- Private households: Persons who live in the same dwelling constitute a private household;
- Occupied residential buildings and their dwellings.
The AHV/AVS insurance number is allocated to all persons listed in the official population registers. The number can be used as a personal identification number (PIN) for statistical purposes. The introduction of a PIN is a key element for data integration.
Data with the AHV/AVS number are regarded as non-anonymised data. For this reason, measures will be needed to guarantee the protection and the confidentiality of the data. The introduction of one or more statistical identification numbers (pseudonymised numbers) specific to each area as well as other technical protection measures will fulfil this function.
Each person listed in population register is given the identifiers for the dwelling they occupy. They are the federal building identification number (EGID) and the federal dwelling identification number (EWID) from the Buildings and Dwellings Register (BDR). This allocation enables household composition to be ascertained on the basis of registers. The EGID is unique nationwide; the EWID is unique within each building and is always assigned in combination with the nine-digit federal building identification number. Further information can be found on the internet page on the EGID/EWID allocation (in German, French and Italian).
Key variables have been defined as another requisite for structuring statistical information. These are recorded in the surveys in standardised form. They allow population groups to be defined and identified in a standardised way. The key variables also generate a lowest common denominator which guarantees that the results of the different statistics and the statistical monitoring of specific population groups are comparable. Documents and links related to the key variables can be found below.