The register census is a joint project of the statistical offices of the Federation and the Länder. The offices cooperate closely with the municipalities and other agencies that keep registers and data. The specialised statistical areas are currently undergoing further methodological development in order to create a modern infrastructure for register-based statistics production.
The register census will continue to provide results for the following specialised statistical areas:
- Population
- Buildings and dwellings
- Households and families
- Labour market
- Education
New methods are being designed in all subject areas. Building on experience gained in previous census rounds, these methods are carefully tested and quality-assured so they can be rolled out on a gradual basis. Where possible, established practices, procedures and IT components of the 2022 Census are consistently reused. A modern infrastructure that uses cloud technologies is gradually being developed for the largely register-based production of statistics. Furthermore, artificial intelligence methods (AI) are tested to examine the extent to which the quality of the results on buildings and dwellings, for example, can be ensured using remote sensing data (satellite images and aerial photographs). Overall, a high priority is attached to safeguarding data quality, which is why the procedures and methods for the register census are constantly evaluated as the project progresses.
As the population figures are very important as a basis for decision-making and planning, the method of register-based data collection must be thoroughly tested. The German Bundestag and Bundesrat therefore adopted the Act on the Testing of Register Census Methods in May 2021. The Act lays down rules, for example, for continuous methodology testing in the area of population statistics. The population registers held by the municipalities will remain the main source of information on population figures. In future, the "signs-of-life approach" will be used to identify undercoverage and overcoverage. This approach examines whether and for whom "administrative signs of life" exist in other data collections held by administrative authorities. As part of the methodological test, data from these comparative registers are transmitted for the first time to the Federal Statistical Office, where they are mainly processed in an automated manner. This enables first assessments to be made on the suitability of the available information and the feasibility of the signs-of-life approach. Furthermore, as part of the methodological test, a record linkage procedure is being developed and examined to see how register data can be reliably linked. For the first time, a procedure is also being established to resolve inconsistencies that come to light when the various register data are matched (place-of-residence analysis). Then, a comprehensive evaluation is carried out to examine to what extent the new methods are actually suitable to determine population figures for the Federation, Länder and municipalities.
The following basic requirements must be met for the register census:
- Data basis: The required data come from different sources. Some subject areas can be covered by existing registers. Legal, technical and organisational rules must be laid down to enable the statistical offices to access the data. In the case of subject areas where nationwide and permanent data sources are not yet available, registers have to be improved or set up. In the long term, for example, owners of residential space will no longer be burdened with a census of buildings and housing once a register of buildings and dwellings has been established.
- Data quality: The data from the different registers are originally intended and primarily used for administrative purposes and are based, in part, on other definitions or standards. They require further processing and their quality must be assured. To this end, common procedures are being developed to ultimately ensure the delivery of census results that comply with the quality standards of official statistics.
- Data linkage: To implement the once-only principle, the required data have to be linked while complying with data protection regulations. Both the technical basis and the legal conditions must be created for this purpose.
- Legal framework: In addition to conceptual work, further national legal instruments must be established for the preparation and conduct of the register census. Moreover, the framework regulation "European Statistics on Population and Housing" (ESOP) is being prepared at EU level. The long-term goal is to conduct the census every year in nearly all subject areas and to complement it with infra-annual results of population statistics