What is a decision boundary in classification?
Updated May 15, 2026
Short answer
A decision boundary separates different class regions in feature space.
Deep explanation
Models learn mathematical surfaces (linear or nonlinear) that partition classes based on input features.
Real-world example
Separating spam vs non-spam emails in feature space.
Common mistakes
- Assuming all models produce linear boundaries.
Follow-up questions
- Which models create nonlinear boundaries?