Resolution:
## Figure 4.
Accuracy, Stability, Between Cluster Distance and Scoring Index for NECS. Accuracy, stability and between cluster distance on the k-means cluster assignments
are displayed in red and the measures on the permuted cluster assignments are displayed
in blue. The scoring index maximizes at 11 clusters (SI = 0.886, 95% CI: (0.876, 0.896)).
The mean score for 9 clusters (0.879) falls within the 95% confidence interval of
11 clusters and thus is as good as 11 clusters but is more parsimonious. and is also
the optimal solution. In general, we expect the permuted stability to increase with
an increasing number of clusters because a larger number of pairs will be consistently
assigned to different clusters since there are more available clusters. However, note
the peculiar trend of cluster stability in this example: the permuted stability decreases
when moving from k = 2 to 4 clusters and then gradually increases. This occurs because
one cluster contains the majority of the subjects for these clusters sizes and thus
the number of pairs of subjects assigned to the same cluster, by chance, is much higher
than in the case where there are equal sample sizes in each cluster. Thus it is important
to account for the permuted measurements when selecting the optimal number of clusters.
Solovieff |