What Is Silhouette in K-Means?

Silhouette in K-Means is a measure of how well the clusters of data points in a dataset fit together. It is used to determine the optimal number of clusters for the dataset, as well as assessing the quality of the clusters produced. The Silhouette value ranges from -1 to 1, where negative values indicate poor clustering, and positive values indicate good clustering.

To calculate the Silhouette value for a cluster, first, its average distance to all other points in the dataset is calculated. This is referred to as the intra-cluster distance.

Second, for each point in the cluster, its average distance to points in other clusters is calculated. This is referred to as the inter-cluster distance. The Silhouette value for a cluster is then calculated by subtracting the intra-cluster distance from the inter-cluster distance and dividing it by the maximum of these two values.

The interpretation of Silhouette values can provide useful information about a dataset’s structure and help guide decisions about how many clusters are appropriate for it. Generally speaking, higher Silhouette values indicate better clustering performance, with values close to 1 indicating that points in a cluster are very similar to each other and far away from points in other clusters. Values close to 0 indicate that there are not enough distinct clusters present in the data; if this happens then more data points should be added or fewer clusters should be used.

Conclusion:

In conclusion, Silhouette in K-Means is an important measure used to assess how well data points have been clustered together into distinct groups. It can be used to determine an optimal number of clusters and also assess cluster quality. High positive values indicate good clustering while negative values indicate poor clustering performance.