Until now, we have learned how to:
Define business problem
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Identify features and label
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Check data quality and leakage
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Create training, validation and test sets
But not every ML problem contains a label, and not every model simply predicts true or false.
Consider three requirements:
1. Predict whether a policy will renew.
2. Discover natural customer groups.
3. Learn which action produces the best long-term result.
These requirements use different learning approaches:
| Requirement | Learning approach |
|---|---|
| Predict a known outcome | Supervised learning |
| Discover hidden groups or structure | Unsupervised learning |
| Learn through actions and rewards | Reinforcement learning |
Today’s core principle:
First identify the type of learning problem. Algorithm selection comes afterward.