I just read this weekend a small article on the VU Magazine that just confirmed something I have always suspected of: according to economist Peter Nijkamp "(...)immigration is an investment that brings a lot of money to the Netherlands." Nijkamp published in April a quick scan of this situation in his work Migration in Balance. According to his research, children from immigrants get diplomas and become successful career tigers, the small companies sector flourish thanks to non-western immigrants and they save whole neighborhoods from empoverishment. Of course, immigration brings problems, and we know they are not a few. But even if you take the problems resulting from immigration into consideration there are no negative effects in the economy of the Netherlands.
Source: VU Magazinepage, issue September #3, 2010, page 21