The problem register
Each problem below has a known answer that no system could deliver cheaply enough to matter. We file them by the kind of fix they need: engineering, when the bottleneck is distribution, scheduling or latency; system dynamics, when it is routing, incentives or verification.
Bloom's 2 Sigma Problem
One-to-one mastery tutoring works; Bloom measured the effect at two standard deviations. It never scaled because expert attention costs too much to give everyone. That cost is what cheap computation now removes.
The Forgetting Curve
Forgetting follows a predictable curve. A scheduler that times each review for the moment just before recall fails turns memory into something you can plan around.
The Proxy Trap
Tie rewards to a test score and people optimise the score rather than the learning it stands for. The loop is wired to the wrong signal. The fix belongs in the incentive.
The Factory Model
Sorting students by birth year is a routing policy borrowed from the factory floor, not a fact about how people learn. Route them by what they have actually mastered instead.
The Latency Problem
Homework set on Tuesday and returned on Friday closes the loop three days too late to be useful. Shortening that delay is a plumbing problem, not a teaching one.
The Signalling Problem
Employers use the degree as a slow, expensive proxy for competence. Verifying specific skills directly is a matching problem, and a solvable one.