Fw: TWOSTEP how to get AIC/BIC for each number of clusters asked for.

[SPSS Support-2]

Hello Art,
   The Information Criteria table (BIC or AIC values for each cluster solution in the autoclustering range) was omitted from the Model Viewer in Statistics 18. A feature request has been filed to add it to the viewer. You can still get the Information Criteria in a pivot table ("Auto-Clustering") in Statistics 18 by running TwoStep from a syntax command and including the subcommand:

/PRINT IC

You can paste the choices from the TwoStep dialogs to a syntax window by clicking the Paste button, then add the /PRINT subcommand in the syntax window.

A couple  of points should be made regarding the TwoStep process:

The first step in the TwoStep process is to place all cases in a Cluster Feature tree. In Step 2. agglomerative hierarchical clustering is applied to the terminal, or leaf, nodes of that tree. You can find the algorithm in the Help->Algorithms meno of Statistics or in chapter form in the SPSS Statistics 17.0 Algorithms guide. The guide can be found on the Support web site at http://support.spss.com. From the "My Product View" menu, choose Statistics, then Documentation. From the "Statistics Documentation" page, choose  "Statistical Analysis Documentation" and then the Algorithms link. Scroll down to the TwoStep Cluster chapter.

All of the the cluster methods available in Statistics - TwoStep, hierarchical (CLUSTER command) and K-Means (QUICK CLUSTER command) - are sensitive to case order and should be run on randomly-sorted data.

David Matheson
Statistical Support
SPSS, an IBM company

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Resolution number: 87760  Created on: Jan 19 2010  Last Reviewed on: Jan 19 2010
Problem Subject:  TWOSTEP CLUSTER Model Viewer does not include values of selected information criterion vs. number of clusters

Problem Description:  I'm using the TWOSTEP CLUSTER procedure in Release 18. The output in the new Model Viewer does not include the listing of information criterion values for a given number of clusters that is given in the Auto-Clustering table. I don't see a way to request this table in the dialog boxes. I'm able to obtain this table by using command syntax and adding

/PRINT IC

to my TWOSTEP CLUSTER command, but when I do so, I get the warning:

The Print subcommand of the TwoStep Cluster procedure has been deprecated and will be removed in the next release. Use the Model Viewer to view descriptive information about the clusters. See the online help for information about the Model Viewer.

I need the information in this table. Can it be added to the output given in the Model Viewer?

Resolution Subject: Enhancement Request Submitted

Resolution Description: 
An enhancement request has been submitted to SPSS Development, requesting that the information in the Auto-Clustering table be incorporated into the new Model Viewer output.

----- Forwarded by David Matheson/Chicago/IBM on 05/18/2010 10:10 AM -----

From:	Art Kendall <[hidden email]>
To:	[hidden email]
Date:	05/17/2010 02:20 PM
Subject:	TWOSTEP  how to get AIC/BIC for each number of clusters asked for.
Sent by:	"SPSSX(r) Discussion" <[hidden email]>

---

TWOSTEP does a hierarchical clustering on a subset of the cases and then applies that to all of the cases.  
If I recall correctly TWOSTEP used to show the AIC/BIC for each cluster number down from the max asked for. E.g., if I asked for a max of 5 clusters it would give the AIC or BIC for 5 down to 1 cluster 5,4,3,2,1.

I haven't used TWOSTEP previously with the latest version but cannot seem to find that in the output?  Was it removed? Is there now a way to see that?

Art Kendall
Social Research Consultants
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