Marked increase in recent years in the number of illegal immigrants

article by

The Rockwool Foundation

For the first time, a scientific analysis has been carried out of the number of illegal immigrants living in Denmark.


The findings reveal that the number of illegal immigrants is greater than hitherto assumed, indicative of a considerable rise in such immigration in recent years. While it is estimated that there were around 15,000 illegal immigrants in Denmark in 2008, the number had increased to more than double that in 2013, standing at approximately 33,000.


The new analysis has been conducted by the Rockwool Foundation Research Unit, and is based on police records of illegal immigrants. The calculations are made on the basis of registrations of immigrants that the police have encountered and charged with residing or working illegally in Denmark. Statistical methods have been used to extrapolate from these figures to estimate the size of the population of illegal immigrants in the country.


As Figure 1 shows, it is not possible to give a very precise estimate on the basis of the available information, but only to indicate a range of figures within a specified confidence interval. This shows the estimated maximum and minimum probable sizes of the population. In 2008 the number is estimated to have been between 9,000 and 21,000. In 2010 the population of illegal immigrants was smaller, between 7,000 and 16,000. Since then the figure has increased dramatically, and in 2013  stood at between 20,000 and 49,000.


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A clear trend

According to Torben Tranæs, Research Director at the Rockwool Foundation Research Unit, this analysis represents a first attempt at a statistical calculation of the number of people living or working illegally in Denmark.


‘Until now, the only figures available have been police estimates. We have gone a step further and made a calculation on the basis of the police records. This does not remove the uncertainty inherent in the estimates, but it does provide a more soundly based figure. We have applied a tried and tested statistical method that is used in many contexts where the size of a hidden population – or one that is hard to register – is to be calculated,’ Torben Tranæs explains.


The most uncertain factors related to the calculations are the size of the annual turnover in the total illegal population, and the proportion of those charged by the police who return after deportation. Danish and Norwegian studies suggest that different groups among the illegal immigrants have very different levels of mobility. For example, it is likely that people who are in the country illegally in order to work are highly mobile, while rejected asylum-seekers are not.


‘Different assumptions can be made concerning remigration and population turnover rates, and for this reason we can only present figures with a very wide margin of uncertainty. Nevertheless, it is very clear that the numbers have increased in recent  years,’ adds Torben Tranæs.


A variety of aspects of illegal immigration are dealt with in this newsletter, including illegal immigration to Denmark for work purposes, and the main nationalities of those charged by the police with illegal  residence and working illegally.