it would be more like different courses are best at teaching the same thing in a particular way that works best with a subset of people, so the top would be made of the set of courses that works with the majority of the population. The problem is that the way humans learn is not exactly understood, is it even a finite set? And what is its diatribution? Can it change through time/culture? Can it be identified in genetic traits? So if the learning methodology changes through time the best courses would also follow with it