[yummyfajitas]

"Another"? Please reread both the post you replied to, and whichever previous post you believe I made pinning the problems of the US on foreigners. I can't recall ever making this claim, and it's so wildly divergent from my general world view that I suspect you clicked "reply" on the wrong post.

Let me just point out that:

a) I don't consider variation in average performance due to composition changes to be a problem (in this post I explicitly disavow that view: http://news.ycombinator.com/item?id=3378157 )

b) in the post you reply to I said that composition changes were too small to affect average performance anyway - i.e., I'm saying Finland has too few immigrants to significantly move their averages.