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

Fionn Murtagh, Pierre Legendre

Research output: Contribution to journalArticlepeer-review


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.
Original languageEnglish
Publication statusPublished - 27 Nov 2011


  • stat.ML
  • cs.CV
  • stat.AP
  • 62H30, 91C20
  • G.3; H.3.3

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