Ward's Hierarchical Clustering Method: Clustering Criterion and Agglomerative Algorithm

Understand

The Ward error sum of squares hierarchical clustering method has been very widely used since its first description by Ward in a 1963 publication.

• It has also been generalized in various ways.
• However there are different interpretations in the literature and there are different implementations of the Ward agglomerative algorithm in commonly used software systems, including differing expressions of the agglomerative criterion.
• Our survey work and case studies will be useful for all those involved in developing software for data analysis using Ward's hierarchical clustering method.