First, like it or not, immigration is correlated with crime rate. There was virtually no immigration in Sweden in 1950. Now, there are lots of immigrants. And, regrettably, it shows.
Secondly, immigrants have worse school performance than natives. In a particularly detailed study from Copenhagen, immigrant children perform significantly worse than ethnic Danes. Worse yet, second-generation immigrants (descendants) are just a tad better than the generation of their parents.
Thirdly, there is a notoriously high level of unemployment among immigrants. The following figures are from France. (In France, it is illegal for authorities to collect data about ethnicity, but there is an academic study available.) You may observe that there is a 35 per cent unemployment rate among African immigrants in France while "only" 16 per cent among the French with no immigrants roots.
Also note that South-East Asian immigrants perform better than French natives in terms of education.