Half of Bloom's two-sigma effect comes from mastery rather than from the tutor, and mastery is exactly the half that education explicitly rejects.

Mastery is actually the part everybody forgets about on that. If you have a tutor that's not mastery based, you won't get the top 2%. One sigma came from the tutor. One sigma comes from mastery, which once again we'll talk about we all accept mastery in in athletics, but we reject it explicitly reject it in education.