[AlexEatsKittens]

The high-school I attended used that method. I was often forced to spend significant chunks of class time teaching other students how to do their work. It was frustrating, and generally a waste of time. It made me hate going to class, because I couldn't spend my time learning, I had to dedicate my efforts to trying to get some kid who would rather be "making beats" on his desk to learn basic math.

I think a better idea would be to have high-performers help teach the kids at the middle of the pack, and leave the low-performers to teachers who have the specific skills needed to deal with their all too common behavioral problems and lack of interest.

[yourapostasy]

Yes, and I suspect that the primary issue of this approach is it doesn't scale. You need top-end teaching talent to pull it off, extremely strong parental support, and a school that has the wherewithal to remove uncooperative students whose behavior crosses a quality boundary, for more intensive support elsewhere (just not in those classrooms). I've seen this approach work well in a private school setting. But that school's endowment was already self-funding (thus tuitions added to the capital funding but had no real impact on operational funding that was largely drawn from interest) so the school had no qualms whatsoever instantly dismissing any disruptive students, and there was a line of previously-passed-over, eager students ready to take their place.

Behavioral problems inside the classroom were extremely rare in that setting (what little existed was negligible and ignorable by public school standards, like simply doodling "to" another student), and the academic atmosphere was far more supported by the students than I've seen in the American public school system. Supporting your anecdotal experience, many of the attending students were either honor roll or in the highest academic tracks in their previous public school lives; at that private school, they were ranked as average.

In the public school system I've never seen this approach work beyond one-off, heroic single-teacher-led efforts. Once that teacher leaves, the approach leaves with them; I've never seen a public school officially run classes this way. Ironically, the "more primitive" one-room schools of American yore were supposedly run this way, but I've never been able to locate academic studies of their effectiveness.

[danielweber]

In high-school calculus, I would arrange to answer the questions other kids in class had, so that I could then ask the teacher the questions that I had.

It wasn't too bad, because I was teaching other honors students.