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manojkuchi
Calcite | Level 5

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How Does SAS calculate Dunn Index or Davies-Bouldin Index for K-means clustering?
Kindly help.
2 REPLIES 2
sbxkoenk
SAS Super FREQ

Hello,

 

I have done a lot of k-means clustering in the recent past and I have to say that, unfortunately, the DaviesBouldin index (DBI) and Dunn's separation index are not standardly available in proc FastClus (SAS/Stat) nor in proc kClus (Visual Statistics). Nor is the Silhouette score (another technique often used for evaluating clustering algorithms and/or determining the optimal number of clusters). SAS uses many typical statistical measures like RMSSTD (root-mean-square standard deviation) and the like for these purposes.

 

For DBI, you will need to start coding. You can probably use the distance measure (variable) output by the k-means clustering algo (distance of observation to the cluster-center as well as the cluster assignment / cluster membership are available in the out= data set).

There is also a useful procedure called PROC DISTANCE (SAS/Stat). Just mentioning it in case you would need it.

 

Good luck,

Koen

 

sbxkoenk
SAS Super FREQ

In addition to my previous response, ... this paper may also be of interest to you:

 

Paper 3409-2019 (SAS Global Forum 2019)
How to Evaluate Different Clustering Results
Ralph Abbey, SAS Institute Inc.

https://www.sas.com/content/dam/SAS/support/en/sas-global-forum-proceedings/2019/3409-2019.pdf

 

Cheers,

Koen

 

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