st: New command for clustering -clustpop-

[Paul Millar <paulmi@nipissingu.ca>]

Thanks to Kit Baum, a new command of interest to -cluster- users has
been uploaded to ssc.

Users of -cluster- are no doubt familiar that each run of the command
on the same data produces different clustering.

A run of cluster is, in effect, a sample (n=1) from the population of
possible cluster groupings.

-clustpop- expands the sample size by running -cluster- many times to
estimate the population group assignments.  The most frequent group
assignment is taken as the estimate of the population and a
statistical test of significance is performed to ensure the lower
bound of the proportion is greater than 0.5.  In other words, users
can be confident, at a given alpha level, that this group assignment
occurs for the majority of cases in the population.  Cases which do no
meet the criteria are set to missing.

I expect that most users will prefer this method to using the
-cluster- command alone.

- Paul
- Paul Millar
Criminal Justice and Legal Studies
Nipissing University
North Bay, Ontario, Canada
www.paulmillar.ca
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