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Silhouette coefficient

The silhouette coefficient measures how well a sample fits its assigned cluster compared with the nearest alternative cluster, typically ranging from -1 to 1.

How 2 Manning books explain it

Statistics Slam Dunk

A silhouette coefficient measures an observation's relative cohesion within its assigned cluster and separation from the nearest other cluster, typically ranging from -1 to +1.

How it is used
Selects an appropriate number of clusters when the elbow plot is subjective or lacks a clear bend.
How deep it goes
Defines and derives the coefficient from dissimilarities, then uses plotted values to choose K without discussing implementation internals.
Examples
Evaluates NBA team clusters formed from standardized payroll and regular-season wins.
What you can do after
Apply it via factoextra's fviz_nbclust() to compare candidate cluster counts in R.

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Cyber Threat Hunting

The silhouette coefficient is a clustering metric that compares an observation's cohesion within its assigned cluster with its separation from neighboring clusters, ranging from -1 to 1.

How it is used
Uses cohesion and separation to choose or validate k in k-means clustering.
How deep it goes
Defines per-point distances, gives the formula and range, and explains computational cost without deriving distance implementation.
Examples
Demonstrates k ranges 2–10 and 2–12 with plots, timing comparisons, and a k = 10 cluster-size countplot.
What you can do after
Evaluate candidate cluster counts with KElbowVisualizer and compare silhouette analysis against the elbow method.

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Related concepts

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