Apparently, the same issue exists in SAS, where there is an option to run the Ward algorithm based only on the distance matrix. Perhaps, a SAS user could confirm that or even check with SAS. Peter -- View this message in context: http://r.789695.n4.nabble.com/hclust-with-method-ward-tp2952140p2965310.html Sent from the R help mailing list archive at Nabble.com.