On Bloom’s Two Sigma Problem.

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Fig. 1 — Bloom (1984) μ₁ = 0σ  ·  μ₂ = +2σ

+2σ

The gap between a classroom and a tutor.

98th

Median tutored student’s rank against the conventional class.

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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 is still education’s open problem. I’m working on it — with AI, in the AI era.

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