International
Tables for Crystallography Volume H Powder diffraction Edited by C. J. Gilmore, J. A. Kaduk and H. Schenk © International Union of Crystallography 2018 
International Tables for Crystallography (2018). Vol. H, ch. 3.8, p. 334
Figure 3.8.8^{a} 

Figure 3.8.8
The use of silhouettes in defining the details of the clustering. (a) The silhouettes for the red cluster in the dendrogram from Fig. 3.8.6(a). (b) The corresponding orange cluster. Both sets of silhouettes have values that are less than 0.5, which indicates that the clustering is not well defined. (c) The silhouettes for the red cluster corresponding to the dendrogram in Fig. 3.8.6(c). The entry centred on a silhouette value of 0.15 is pattern 3. This implies that pattern 3 is only loosely connected to the cluster and this is demonstrated in part (d), where pattern 3 and the most representative pattern for the cluster (No. 9) are superimposed. Although there is a general sense of similarity there are significant differences and the combined correlation coefficient is only 0.62. (e) The silhouettes for the orange cluster corresponding to the dendrogram in Fig. 3.8.6(c). The silhouettes imply that this is a single cluster without outliers. (f) The silhouettes for the green cluster corresponding to the dendrogram in Fig. 3.8.6(c). The clustering is poorly defined here. 