Household generating procedure – more than forming households
Besides determining the official number of inhabitants, a major goal of the census is to collect data on both the number and structure of households and their housing situation. As this information is however not included in the population registers, a method was developed to establish these household relationships.
In the course of the household generating procedure, variables are combined from the different data sources used for the 2011 Census. They are analysed and linked to form households in dwellings. The relevant data sources include the following: register of addresses, census of buildings and housing, population register, a survey conducted at special facilities, sample survey and survey to clarify discrepancies. In this way, results regarding household relationships can be obtained in great regional detail. The household generating procedure comprises several stages:
Establishing first household relationships using direct register data
In the form of links, the population register contains clear information on how persons are related with each other. The first step of the household generating procedure is designed to show relationships such as marriages, registered civil partnerships, relationships with descendants (typically minor children) and legal representatives, which are registered for two persons at the same address. Thus this initial step allows the establishment of first household relationships.
Analysing the data on main tenants/owner-occupiers
The population register does not contain any information on which dwelling a person is living in. Therefore, in a second step, the names of main tenants/owner-occupiers of dwellings that were yielded by the census of buildings and housing are matched with and linked to the names of the people included in the stock of census data taken from the population register. Members of the same household who were identified in the first step are assigned to the same dwelling.
Generating households using indirect register data
The third step of the household generating procedure is designed to gather more information about people living together in the same household. Based on information regarding names, ages and arrivals, a documentation of previously unknown relationships in the stock of census data taken from the population register will be facilitated. Also, new forms of households and cohabitation are shown to supplement the typical family relationships between father, mother and child. Information on the number of people living in a dwelling that was yielded by the census of buildings and housing is taken into account, too.
Integrated correction procedure
The 2011 Census included a household survey. Besides collecting data that were not available from registers, the main goal of the sample survey was to gather information on the number of people who were either not covered or covered by mistake in the population registers of each municipality with 10,000 or more inhabitants. Here, the point was also to describe these missing or outdated register entries using demographic variables. In this next step of the household generating procedure, the individual data are therefore corrected, that is, adjustments are made for outdated or missing register entries in order to obtain high-quality records of individual census data for flexible subject-related and regional evaluations.
Generating households based on statistical criteria
Households which could not yet be allocated to a dwelling up to this stage of the process because the name of the main tenant/owner-occupier was missing are now linked to dwellings not yet comprising a household. For this purpose, variables such as the floor space of a dwelling and the household size are taken into account. If after this there are still households that could not be allocated to a dwelling, they will be linked to households that were already allocated to a dwelling. To reflect the distribution by household types in a realistic manner, extrapolated results from the household sample survey are integrated in the above process. In this way, all people or households at a given address can eventually be allocated to a dwelling and the residential households defined in the census be formed.