AI engineering glossary · Classical ML algorithms
What is decision boundary?
Decision boundary: The surface in feature space where a classifier switches from predicting one class to another. In two dimensions it is a line or curve. Its shape depends on the algorithm: straight for logistic fitting, jagged and box-like for trees, curved for kernel methods.
Decision boundary: an example
For a loan model using income and debt, the boundary might be the line debt = 0.4 * income; applicants above it are predicted to default.
Related terms
More Classical ML algorithms terms
- Decision stump
- Decision tree
- Dendrogram
- Dimensionality reduction
- Elastic net
- Elbow method
- Ensemble learning
- Entropy
Where you learn it
Decision boundary is part of the AI Engineering Program, which teaches it with notes, a hands-on lab and an exam. The first lesson is free.