Interesting report and interview on the relationship between test scores of 'crystallized skills' (what schools teach) and 'fluid intelligence' (basically, the ability to think). Of course, there is none. Futhermore, teaching makes almost no contribution to logical thinking and problem solving in novel situations, at least for the 1400 eighth graders being studied.

"where a school accounted for approximately 1/3 of the variation in state test scores, they accounted for very near zero of the variation on these fluid cognitive skill measures."

This is hardly surprising in a world where the success of teaching is measured by standardized tests, and teaching is focused on achieving good results in those tests. The researchers are right to observe that crystallized skills are important, so this is not necessarily all bad news: schools appear to have some effect. However, I strongly suspect this is a short-term effect (as long as is needed to pass the test) and much less than it could be due to the extrinsic motivation designed into the system which actively degrades the students'  intrinsic motivation to learn. Whether or not that's true, it's a terrible indictment of an educational system that it affords no opportunities to develop the thinking skills that matter more. These skills are not measured in the standardized tests nor could they be measured in that way without destroying what they seek to observe. This doesn't mean that we need better tests. We need better education.