Few things inspire nationwide hand-ringing among the American elite like an international survey pointing out how un-elite we are. The United States, which likes to think of itself as number one in every list that matters, typically chimes in around 20 or 30 when our kids match up against foreign students in international math and science studies. But here's a great post about how these surveys get education achievement so wrong.

Education reformers sometimes encourage us to think of schools like a business. This leads to a list of sensible sounding goals. Clarify incentives for students and teachers. Test progress iteratively. Balance costs and benefits to invest in pedagogy that works. Reward success.

But if we're going to apply economic lessons to kids' brains, let's also think about the economic concepts of input and output. That is, think about who we're teaching and what we expect of them. Finland, one of the countries that consistently rocks these tests, has very few immigrants. The United States, on the other hand, is one of the most-immigrant rich developed countries.

Why does that matter? Because around the world, immigrants tend to perform worse on standardized tests.

The author explains how he did well in a bad school in Tehran and poorly in a good school in Sweden because he hadn't mastered the second country's language. This is common, he says: "In almost all European countries, immigrants from third world countries score lower than native born kids."