Unlike with a traditional census, where all citizens are interviewed directly, the 2022 census is once again based on existing administrative registers. The primary source of data is the population registers in German municipalities. However, some of the population were also interviewed directly as part of a survey of randomly selected households, in order to improve the quality of the database.

As citizens who live in residential establishments and collective living quarters are not fully recorded in the population registers, a full survey was conducted for all residents in residential establishments such as student halls of residence. In collective living quarters (e.g. correctional facilities and hospitals), the facility managers had to provide information on behalf of the residents.

For the census of buildings and housing carried out during the 2022 census, all private owners of dwellings or buildings with living space were interviewed, as were the owners of multiple properties who act in a commercial capacity, as well as property managers and other persons entitled to manage and use buildings and housing.

The online questionnaire offers a number of advantages for respondents and statistical offices. Data submitted online are more accurate than information obtained from paper questionnaires. The results can also be published more quickly, as it does not take as long to process the data. And last but not least, online surveys are much more sustainable than postal surveys with printed questionnaires. That’s why our aim is to make the online questionnaire the standard form of submission. This applies to the household survey and the census of buildings and housing. For this to work, our preparations and processes had to be geared towards the online survey from the very beginning.

The most important area of improvement concerns the accuracy of our results, which can be achieved by increasing the percentage of online submissions. More plausible results can be obtained from an electronic questionnaire. As soon as respondents enter their information, it is checked to make sure it is plausible and complete, and potential spelling mistakes are displayed. The aim is also to make the process as comfortable as possible for citizens. The targeted filter function ensures that respondents are only shown the questions they actually have to answer during the census of buildings and apartments. This makes the questionnaire easier to complete – and in just a few minutes.

By printing fewer questionnaires, we can ultimately help to preserve natural resources. This is both more cost-effective and better for the environment. If we piled up the questionnaires completed for the census of buildings and housing during the 2011 census, the stack of paper would be even higher than Mount Everest (8,848 m). By printing fewer questionnaires, we can also reduce our transport routes, improve our carbon emissions and cut our printing and postage costs. In addition, we can greatly reduce the costly manual post-processing of paper questionnaires.

A survey of randomly selected households was conducted during the census. This was done for two reasons. On the one hand, the aim was to make sure that the official population figures are accurate by detecting any over-coverage and under-coverage, thereby revealing any information that is erroneous or missing from the database. On the other hand, the random selection of households enabled other data to be recorded which are not contained in the population registers or which are not sufficiently reliable there. This structural population data serve as the basis for political decisions made at national, regional and local level with regard to the population, the economy, social affairs, housing, spatial planning, transport, the environment and the labour market.

An above-average number of register errors can be assumed for residential establishments and collective living quarters due to the relatively frequent change of residents and inadequate reporting. That’s why a full survey took place in these special areas. In residential establishments, everyone who lived there on the census date was interviewed directly. In collective living quarters, the facility managers were required to provide information on behalf of the residents.

In residential establishments, residents could have been interviewed again as part of the survey of randomly selected households. Some examples of residential establishments include student halls of residence and workers’ hostels where the residents are presumably responsible for managing their own household affairs. By contrast, people living in collective living quarters are not usually responsible for managing their own household affairs and are looked after and/or monitored in the collective living quarter. Some examples of collective living quarters include old people’s homes, nursing homes, psychiatric institutions, correctional facilities and collective living quarters for refugees.

As there is no uniform administrative register for recording the full inventory of buildings and housing in Germany, the 2022 census not only includes the official population figures, but also a census of buildings and housing. The aim is to record all buildings with residential space throughout the country, as well as inhabited accommodation and the apartments located in them, on the census date. All owners, administrators and other persons entitled to manage and use buildings and housing were obliged to provide information. The results will play an important role in shaping housing policy and spatial planning measures.