It is always a temptation for teachers to want to innovate their curricula because what they’ve been teaching is old hat. Of course it’s old hat – to the teacher, who has been teaching the same thing for decades. But it’s completely new hat to the students! We’re all familiar with stories about history students who, having gone through the revised curriculum, know everything about the female mill workers of Lowell, Mass., but nothing about the political theory behind the American Revolution, or who know all about the hard tack consumed by the sailors in the Royal Navy, but not much about battle of Trafalgar or the Napoleonic Wars of which it was a part. The teacher might know all about it from when he himself was a student, making all the new information an exciting supplement to his knowledge base. But the student usually doesn’t, producing the effect of a building with a weak foundation, ramshackle frame, and gorgeous three-season deck.

Teachers need to be more humble about this.