I want to just show one of his plots:
Moreover, if it were true that Poverty causes Achievement, the policy implications would be clear and important. In order to improve math and science achievement in the U.S., we wouldn't need to focus too much on teachers, teachers' unions, charter schools, and so on. Rather, we would only need to find a way to decrease poverty. Simple. Okay, maybe not so simple...Again, I encourage everyone to read his post and for me it reinforced the importance of getting causation right.