Figure 2
From: A tutorial in displaying mass spectrometry-based proteomic data using heat maps
Agglomeration Methods. An illustration of the difference between (a) complete linkage and (b) the Ward method of agglomeration. When merging 3 groups into 2 using complete linkage, 16 - 9 = 7 > 9 - 1 = 8, so 9 is grouped with the larger numbers. Using the Ward method, the groups {1, 3, 3, 4, 5}, {9, 15, 16, 16} produces an ESS2 = 42.8, while {1, 3, 3, 4, 5, 9}, {15, 16, 16} produces ESS2 = 37.5, so the second merge strategy is used.