title: SAS Enterprise Miner Clustering - Problems with CCC
body: <p>I am trying to find an optimum cluster size using the Cluster Node and CCC criterion.</p>
  
  <p>The Automatic setting (default) configures SAS Enterprise Miner to automatically determine the optimum number of clusters to create using either Ward or Centroid method. However, I have some serious problems with the automatic method, the selection of the "optimum" cluster size, and the reported statistics. The options chosen were Cluster Method=Ward, Prelim Max=50, Min=5, Final Max=50, CCC Cutoff=3. </p>
  
  <p>Note the following Cluster Node result. <a href="https://i.stack.imgur.com/oCZKE.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/oCZKE.jpg" alt="Cluster Node Result Screenshot"></a>.</p>
  
  <p>The Output shows three candidates for optimum number of clusters k=6, 10 and 46 with CCC=-104, -80 and 163. The best was selected, i.e. k=46 with CCC=163. At the same time, the Cluster Statistics report states that the resulting CCC was 294, however, the maximum CCC within the available range was only 163 (of k &lt;= 50). Interestingly when the preliminary maximum is increased gradually to 500, the discrepancy between the two reported values of CCC is getting smaller.</p>
  
  <p>The CCC vaules shown in the Output are consistent with the chart and the selection of the optimum k for clustering. The CCC value in the cluster statistics table is a pure fantasy and  I cannot see any way of translating it to anything meaningful.</p>
  
  <p>Is there something wrong with my analysis?</p>
  
  <p>P.S. I've read the Cluster Node help.</p>