Database on Immigrants in OECD Countries

Bibliographic citation:
Organisation for Economic Co-operation and Development: International Migration Statistics. UK Data Service. https://doi.org/10.5257/oecd/ims/2015-10

Most countries that provided census or register data have applied a random rounding procedure intended to prevent the disclosure of individual information. This procedure consists in randomly rounding each data cell to the closest upper or lower multiple of 3 or 5. Any figure extracted from the database reflects this procedure and the population totals or subtotals may therefore vary slightly from one table to the other. In order to improve the reliability of the population estimates from the labour force surveys, several surveys over the period 1998-2002 have been stacked and the figures have been averaged over this period. The significance thresholds provided by Eurostat for individual surveys were adapted to reflect the increased sample size resulting from this operation, taking into account the overlap between two successive surveys. No cell with a population below these calculated thresholds can be published, and the cells are assumed to have a zero population.

The sources for this database are mainly census data, from the 2000 round of censuses. Census data were used for 22 countries. Countries not taking periodic censuses but keeping population registers have provided data extracted from these registers; this is the case for four countries: Denmark, Finland, Norway and Sweden.

For some countries, not all themes covered in the database are present in the national census or register. Labour force surveys, provided by Eurostat and averaged over the period 1998-2002, have been used to fill the gaps where possible.

The International Standard Classification of Education (ISCED; cf. UNESCO 1997) was used as a baseline, but groups have been aggregated as follows:

Primary level: ISCED 0/1/2.
Secondary level: ISCED 3/4.
Tertiary level 1: ISCED 5A/5B.
Tertiary level 2: ISCED 6.


Some countries were not able to provide data distinguishing between Tertiary 1 and Tertiary 2: this was the case for Austria, France, the United Kingdom, Hungary and Japan. Whenever labour force surveys had to be used, because of the limited sample size, levels ISCED 5 and ISCED 6 were aggregated into a single tertiary education category.

A more compact classification with three levels (Primary, Secondary and Tertiary) has therefore been produced to reflect the lowest common denominator.
Labour Force Status:

The most detailed classification of labour force status in the database comprises five categories:
Employed
Unemployed
Inactive - student
Inactive - retiree.
Inactive - other

For some countries, the cause of inactivity is not available. There is no detail at all on the cause of inactivity for Canada, New Zealand or Poland. Nor is the cause of inactivity recorded in the database for Germany or the Netherlands, for which the source is the labour force survey.

Therefore a broader classification common to all countries has also been established, with three categories: employed, unemployed and inactive.

Field of Study:

Data on the fields of study only cover the people with a tertiary education. The classification is made according to the major groups defined in ISCED 1997 (see Table A.8 for the details of these groups).