On Bloom’s Two Sigma Problem.
Fig. 1 — Bloom (1984)
μ₁ = 0σ · μ₂ = +2σ
In 1984, Benjamin Bloom showed that students tutored one-on-one performed two standard deviations above peers taught in a conventional classroom. Forty years on, closing that gap at scale remains education’s open problem. I’m working on it — this time, with AI.
