Inertia K Means Cost Function

Definition:
Inertia is the sum of squared distances from each point to its assigned cluster center. Lower values indicate more compact clusters.

Is this WCSS?

Use in K-means:

• Used to determine optimal $k$ via the elbow method: WCSS and elbow method
• Sensitive to scale and number of features

Exploratory Questions:

• How does inertia correlate with cluster separation?
• Is it meaningful when clusters are non-spherical?
• What are its limitations in high-dimensional spaces?

Related:

• Cluster Density