Hello
I am interested in fitting a tree model for a variable which is ordinal, and
where the distribution is far from uniform.
More specifically, I would like to investigate drug use, which we have
operationalized as hardest drug used in the last year (none, marijuana,
cocaine/heroin (not crack, and not injected), crack, and any injected drug.
The distribution in our sample is
none - 186 marijuana - 136 cocaine/heroin 137 crack - 41 injection - 28
The ordinality means that the misclassification costs are uneven (e.g.,
calling a marijuana user a nonuser is no big deal. Calling an injector a
nonuser is much more serious).
I have been unable to find out how to do this in the S-Plus manuals; although
the classic reference (Breiman et al., 1984) offers some hints, they do not
provide any code (nor do they indicate that they used S-Plus at all).
Any help appreciated
Peter L. Flom, PhD
Assistant Director, Statistics and Data Analysis Core
Center for Drug Use and HIV Research
National Development and Research Institutes
71 W. 23rd St
New York, NY 10010
(212) 845-4485 (voice)
(917) 438-0894 (fax)
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