Twostep cluster analysis example

For this example, we return to the USA states violent crime data example. Recall that TWOSTEP CLUSTER offers an automatic method for selecting the number of clusters, as well as a Likelihood distance measure. We will run it to show some of the visuals in the model viewer output.

The approach here is to:

1. First run TWOSTEP CLUSTER in automatic mode to identify a tentative number of clusters.
2. Then run TWOSTEP CLUSTER again with a specified number of clusters.

Here is the SPSS code for the first run:

TWOSTEP CLUSTER
 /CONTINUOUS VARIABLES=MurderR RRapeR RobberyR AssaultR  BurglaryR LarcenyR VehicleTheftR
 /DISTANCE Likelihood
 /NUMCLUSTERS AUTO 15 BIC
 /HANDLENOISE 0
 /MEMALLOCATE 64
 /CRITERIA INITHRESHOLD(0) MXBRANCH(8) MXLEVEL(3)
 /VIEWMODEL DISPLAY=YES
 /PRINT IC COUNT SUMMARY. 

Here are comments on the SPSS code:

• In a step not shown, the variable names were shortened. This makes for a more informative model viewer output.
• /CONTINUOUS specifies the continuous variables...