One note on John Sides’ post about that subject: It is interesting to see that Sweden and Denmark have almost the same score when people are asked whether immigration tended to improve or worsen crime while the political approach to immigration differs wildly between the two countries.
There is of cause a second, trickier layer: The real impact of immigration on crime, as opposed to the perceived impact, which obviously may vary between countries just as the level of immigration varies. This quote sounds familiar:
The finding that incarceration rates are much lower among immigrant men than the national norm, despite their lower levels of education and greater poverty, but increase significantly over time in the United States for those who arrived as children and especially among the second generation, suggests that the process of “Americanization” can lead to downward mobility and greater risk of involvement with the criminal justice system for a significant minority of this population.
Update: Danish TV2 published this story where according to a study a) youths with an immigrant background are overrepresented in special security institutions but b) the significant variable isn’t immigrant but refugee background. I’m not really surprised: First, I would expect refugees to have a messier background than “ordinary” immigrants and, second, the often drawn-out asylum process only adds to the problems. This isn’t linked to immigration and immigration policies so much as to refugee policy.
(Oh, and there are no points to the reader who first post a comment about the Swedish elite conspiracy to hide the truth about immigration)