“I’d been looking around the world for clues as to what other countries were doing right, but the important distinctions were not about spending or local control or curriculum; none of that mattered very much. Policies mostly worked in the margins. The fundamental difference was a psychological one. The education superpowers believed in rigor. People in these countries agreed on the purpose of school: School existed to help students master complex academic material. Other things mattered, too, but nothing mattered as much.”