Throughout the ongoing controversy in Canada over the end of the mandatory long form census, many have argued that Denmark (among other Scandinavian countries) no longer conducts a census. I asked fellow data professional and blogger Henrik Liliendahl Sørensen to explain how his country manages population data as a guest contributor to BIProfessional.com:
Census Options: The Scandinavian Model
The Scandinavian model exemplified through the Danish variant does not require citizens to periodically fill out a census form. Census information is extracted automatically when needed from administrative registers.
When a new Danish citizen is born (typically at a hospital) the child is assigned a national identification number within minutes. The ID is linked to the mother’s ID and, if she is married, also automatically to her husband as father as well. Otherwise the father’s ID (if possible) is obtained within a short time. In case of immigration, procedures exist for assigning national ID and collecting basic data. All information is kept in a centralized citizen registry.
The less romantic consequence of a marriage is that the two national IDs are linked in the citizen registry from that day forward. A divorce will result in a deactivation of the link.
All buildings, and if not a single family house, all the apartments within, are reflected in a centralized registry. When establishing a new house or apartment a lot of data is captured and if the residence is changed the data will be updated.
Your place of living is a relation between your national ID and the unique ID of the residence having the valid-from-date being the day you moved in until the day you move on is registered as the valid-to-date.
Practically all events in the life of a citizen involving a public sector body are logged with the national ID. This also includes healthcare and interaction with financial services and employer relations where mandatory reporting exists.
The technical opportunities for compiling census information based on these registrations are plenty. However every case must be approved by a body within the authorities and wherever possible data must be made anonymous in the actual processing.