Data on migration dating back to 1966

The migration among the population is collected in a dedicated file. The file contains all migration from 1966 to the most recent year. The file has one line per migration over the entire time period, and is well suited for studying migration over time. No checks have been made for internal consistency in this collection. This means that there may be cases where out-migration is directly followed by internal migration – i.e. without any indication of in-migration.

1. Quality

The statistical data is based on data from the Central Population Register, and the quality depends on whether people report when they migrate; not everyone does. Single students can choose whether or not to report moving out of their family home, and many of those who have an obligation to report fail to do so. This is particularly the case for out-migration, but also in other cases. Over time, many of the unregistered migrations will be captured during reviews of the Central Population Register, which means that some data will only emerge long after the event. However, not all migration is captured.

Figure 1 shows the migration for the period 1966–2015, with the exception of migration within municipalities. The striking aspect of the figure is the migration between municipalities in 1970. In 1969, there were 189 000 migrations and in 1971 the figure was 191 000, compared to 232 000 in 1970. This increase was due to the discovery of a significant time lag in migrations in the Population and Housing Census in 1970.

Figure 2 shows the differential between official statistics and migration in the file on the number of migrations broken down by type. The fluctuations are due to the time lag, i.e. late reporting. The plusses and minuses cancel each other out over time.

2. File content

Population

Registered migration encompasses everyone who has a Norwegian personal identification number. Asylum seekers can live in the country for several years before they are granted asylum (or not). For this group, the in-migration date (hdato) is nowadays normally set at the date on which they were granted residence and received a personal identification number. Between March 1987 and January 1994, asylum seekers were generally regarded as immigrants to Norway – and therefore also as residents – even if the application for a residence permit was still being processed. Before and after this period, only asylum seekers with a residence permit (and thus a personal identification number) were registered.

Variables

• All of the variables have a text/string format.
• ‘Missing’ indicates an empty field.

3. The variables

The following is a review of the variables that require some type of description.

Type of migration (rec_type)

Code list

1 = migration between municipalities
2 = out-migration
3 = in-migration
4 = migration within municipalities

Date of migration (hdato)

Format: yyyymmdd

Years in the migration statistics (statdato)

The year that the migration was entered in the official migration statistics. In the vast majority of cases, this is the same year as the migration took place. However, some migrations are reported several years later, and are thus entered in the statistics the year that the report was received.

Out-migration and in-migration countries (fraland_åå and tilland_åå)

Until the end of 1974, a two-digit country code was used, with only the main out-migration and in-migration countries having their own codes. The remainder were coded under ‘The rest of Europe’. In 1975, three-digit codes were introduced. These still apply, but are updated continuously as old countries disappear (the Soviet Union, Yugoslavia, etc.) and new ones emerge.

Coverage of out-migration countries is good, but there are major shortcomings in the in-migration countries since many of those who migrate out of the country do not report where they are moving to.

Migrating between municipalities in Norway

Data on migration is available dating back to 1966. The quality of data is higher for later years than earlier ones. For the level below municipalities: district, basic statistical unit, cadastral unit number, property unit number and address, data is available from 1999. Obtaining data for research purposes at the basic statistical unit level or at a more detailed level requires special justification.

From and to districts (f_bydel og t_bydel)

District codes must be combined with municipality codes. There are official districts in the four largest cities (municipalities): Oslo, Stavanger, Bergen and Trondheim. In order to ensure that data is entered correctly, either the municipality must be selected first, or a new variable must be created consisting of municipality and district.

On 1 January 2004, the municipalities of Oslo and Trondheim were divided into new districts. The number of districts in Oslo was reduced from 25 to 15, and the new geographical areas of Sentrum and Marka were formed. The number of districts in Trondheim was reduced from 6 to 4. In Oslo, new codes were introduced. In Trondheim, codes have been reused, which means that the same code has different content before and after 2004.

From and to basic statistical units (f_gkrets og t_gkrets)

In the file, the basic statistical unit is specified with four positions. A complete basic statistical unit code consists of eight digits. The first four digits refer to the municipality code (fra_kommnr/til_kommnr), while the last four digits represent ‘from basic statistical unit’ and ‘to basic statistical unit’ (f_gkrets/t_gkrets). In order to ensure that data is entered correctly, either the municipality must be selected first, or a new variable must be created consisting of municipality and basic statistical unit.