- Block 9 — Generalization
- Objective
- turn the diagnosis of chapter 031 into a decision procedure.
Establish that no remedy applies without a prior diagnosis, then work through
the full catalogue of corrective actions — more data, better data, augmented
data, fewer columns, less capacity, a penalty on the parameters, an interrupted
optimization, an ensemble of decorrelated predictors, a smoothed target, a
simpler problem — measuring the effect of each one rather than asserting it.
Know the geometry that makes an L1 penalty produce exact zeros and an L2
penalty never produce them, read a cost-complexity pruning path, read a
stopping trace, and price a remedy against the cost of buying more labeled
rows. Close with a triage table that names, for each symptom, the cheapest
remedy that works. Cover the reverse case as well: what to do when the model
underfits, where every lever in this chapter must be pushed the other way.
- Estimated duration
- 75 minutes
- Prerequisites
- chapters 025 (feature selection), 026 (train, validation
and test), 031 (overfitting and underfitting) and 032 (bias-variance tradeoff)
- Associated quizzes
033.1-quiz-diagnosis-first.md to
033.9-quiz-choosing-the-remedy.md