The Challenges of Population Statistics, and How to Tackle Them with the Help of Registers
Population censuses are the oldest statistics activities in human history. Their history goes back thousands of years. Researchers laid down the rules for modern population censuses at an international conference of statisticians more than 150 years ago. However, by now, these rules and frameworks have proved too narrow for the demographic development: it has become considerably more difficult to question people, because people value their privacy and do not wish to disclose their data.
This is why the future perspective lies in making the greatest possible use of the existing data to produce statistics. Registers are the primary source for such data. However, accurate statistics can be produced only by using several registers together. If more initial data is available, it is possible to obtain better quality results, in principle.
Registers have been used in national statistics in Estonia since the census of 2011. The primary task that was solved with the help of a dozen of registers was the estimation of the undercoverage of population census. Next, the residency index was developed as a linear combination of “signs of life”, with the help of which it is possible to estimate the number of permanent residents in a country in a current year. The signs of life show the activity of a person in national registers in the year preceding the year of observation. This index is also used to estimate international migration, because it allows estimating the volume of unregistered migration which is comparable to registered migration in volume. With the residency index, it is also possible to estimate the number of commuters and transnational people.
Another significant problem is the estimation of the number and membership of families in the situation where families are created without legally contracting a marriage or registering a partnership. The partnership index, which is a linear combination of the partnership indicators obtained from registers, has been established for that. A location index is also being established which will link households and dwellings, and will allow verifying if a household is residing in their registered residence or not, and, for the purposes of correct statistics, to link every household with the dwelling in which it actually resides.