Maybe a better comparison would be algebra and geometry since he taught those classes but other teachers did as well. Did his students perform any better than the students of other teachers? I would say not although I don't have the data to back it up. I had another teacher for algebra and then him for geometry and when I was in his geometry class with other students that had him for algebra I felt we were even. I never felt like the kids who had him for algebra were way ahead of me when it came to doing the algebra that came up in geometry.
Maybe a better comparison would be algebra and geometry since he taught those classes but other teachers did as well. Did his students perform any better than the students of other teachers? I would say not although I don't have the data to back it up. I had another teacher for algebra and then him for geometry and when I was in his geometry class with other students that had him for algebra I felt we were even. I never felt like the kids who had him for algebra were way ahead of me when it came to doing the algebra that came up in geometry.