Identifying permanent residence in the Population and Housing Census
The places where people live have been recorded in one way or another for centuries. Previously, the place of registration could have been a church, municipality government, city address board, housing board or the Population Register. In recent decades, developed countries have found that register data are usually more accurate than survey data, and so population censuses have also begun to use them. Back in 2011, eight European Union countries conducted the census on a register basis: in addition to the Nordic countries, the Netherlands, Belgium, Austria and Slovenia.
The organisation and mandatory registration of residence vary from country to country. There are countries where prompt registration of actual residence after a change of residence or arrival is mandatory and non-compliance will result in sanctions. There are countries where registering a place of residence in some city is a special benefit, which can be considered as a wage supplement, for example. In many countries, many important services, such as postal services or healthcare, depend on the place of residence.
What is considered when determining a permanent place of residence?
In Estonia, the registration of residence is mandatory, but neither the state nor local governments monitor whether people have registered their actual permanent residence or a dwelling located in another area that offers certain benefits (a prestigious school, good kindergarten, free use of public transport, etc.). Local authorities are often primarily interested in maximising the population number and are therefore prepared to let the “fake habitants” registered in their area slide.
For the Population and Housing Census, a permanent residence is a dwelling where a person has lived or intends to live for at least 12 months. There are three important exceptions to be considered. First, if a person is studying in a higher education institution or in a post-secondary vocational school, their permanent residence is at the location of the educational institution. Secondly, if a person attends a general education school, their permanent residence is the permanent residence of the parent(s).
In the third case, if a person works and lives in a place other than the family’s usual residence but he or she regularly visits the family and spends most of the time there, his or her permanent residence is considered to be the family's usual residence.
Use of register data is a modern approach
The use of register data for census is a modern and reasonable approach, especially in Estonia where technology is at a high level. However, the use of registered residences as permanent residences for the census reveals several bottlenecks. For example, a place of residence where the person does not actually live is registered in order to receive benefits. Thus, in the countries where accurate registration of residence is mandatory and monitored, it is relatively easy to use registered places of residence as permanent residence for census purposes. In the remaining countries, additional data and methods have to be used to solve the problem.
After the census in 2011, it became clear that the results of the census and traditional population statistics are not sufficiently accurate in Estonia. For example, the difference in population estimates between the population register and the population census was about 5%. In order to obtain a more accurate result and to create an opportunity to estimate the population also in-between censuses, it was decided that as many national registers as possible would be used in addition to the population register.
Thus, a residency index was developed, which is assigned each year to each potential resident of the country and which shows the probability that this person is a permanent resident of the country in the reference year. The residency index is based on signs of life, i.e. documentary traces of a person’s activities or stay in the country recorded in the registers.
However, it is reasonable not to use only the data obtained from the registers that are being corrected, but to use big data from other sources as well. By combining big data with other signs‑of‑life type of information, it is possible to obtain reliable, meaningful and applicable results.
A household consists of people living in the same dwelling
In a register-based census, a household is all people living in the same dwelling, regardless of whether there are economic or kinship ties between them. (Life) signs, such as signs of partnership, help to identify additional household members, but these signs may not always be present.
For practical reasons, sometimes people who are not family members, such as parents of partners or other relatives, also live with the family. A family with additional members forms a household, but a family without additional members or a single person living alone is also a household.
There are currently far more dwellings than households in Estonia. The situation is thus radically different from the Soviet era when there was a great shortage of housing. Currently, some of the dwellings are just cottages and garden houses suitable for short-term living in summertime. At the same time, there are also dwellings suitable for year-round use in which no one lives. Some are brand new; others are old. Some households have organised their life so that they live in several places. All this needs to be considered when matching households and dwellings.
Data are combined for accurate results
A good indicator of whether and when people live in a dwelling are electricity consumption data, which are big data. In principle, by monitoring the annual time series of electricity consumption, it is possible to find out which dwellings are permanently used, which are occupied from time to time, for example during the summer period, and which are visited only a few days a year or are unoccupied.
In many cases, it turns out that the most probable dwelling of a household is the one that is registered in the population register. This meets expectations, as research also shows that about 80% of people indeed live in the place that they have registered. However, it is important to detect erroneously registered people and households and find their actual residence. Of course, this does not mean that the person's place of residence would be changed in the population register or a message would be sent to the person, but the corrected data are a basis for census results and calculations of population statistics.
The most differences become clear when determining the residences of young people
The biggest problems are related to identifying the dwellings of young adults. International rules state that students should have their permanent residence in the place of study. However, in Estonia, young people who have lived away from their place of study often do not stay there for most of the year, regularly visiting their parents’ home and moving around in Estonia and abroad in their off-time. If they have not yet acquired a permanent residence, they live with their parents according to registers, which is gladly confirmed by their parents who usually consider them as their household members in surveys.
Defining a partnership for young people is also difficult when they have very few features that tie them together: no common residence, no children, no possessions or responsibilities. It often does not have to be a permanent relationship, as forming these happens later and later these days.
In cases of families and households with children and working parents, there is purposeful and deliberate incorrect registration of permanent residences. The seemingly reasonable distribution of school and kindergarten places based on residence is not suitable for every family due to different reputations of childcare institutions and family logistics. The simplest solution is then to register a permanent residence in a more favourable area, for example by using the dwelling of people they know. There are other reasons for falsifying residence data: free public transport, land tax credit for their home, a discounted ferry ticket to the island of their summer home, etc. However, as most people also have signs in registers that indicate their actual place of residence, it is often possible to replace the erroneous place of residence with the actual place of residence for the Population and Housing Census.
Data from large-scale surveys (the Estonian Labour Force Survey and Estonian Social Survey) are used to test the algorithm for the formation and placement of households and families. Comparing these data with the data of the population register, the accuracy and adequacy of household data significantly improves. However, the accuracy of the data certainly does not reach the accuracy of past censuses, such as the 1934 and 1970 censuses, when the population was local, people submitted their data openly and all dwellings were inspected twice – once before and once after the census moment.