[R] Follow-up about ordinal logit with mixtures: how about 'continuation ratio' strategy?
Frank E Harrell Jr
f.harrell at vanderbilt.edu
Thu May 10 14:38:54 CEST 2007
Paul Johnson wrote:
> This is a follow up to the message I posted 3 days ago about how to
> estimate mixed ordinal logit models. I hope you don't mind that I am
> just pasting in the code and comments from an R file for your
> feedback. Actual estimates are at the end of the post.
. . .
Paul,
lrm does not give an incorrect sign on the intercepts. Just look at how
it states the model in terms of Prob(Y>=j) so that its coefficients are
consistent with the way people state binary models.
I'm not clear on your generation of simulated data. I specify the
population logit, anti-logit that, and generate binary responses with
those probabilities. I don't use rlogis.
See if using the PO model with lrm with penalization on the factor does
what you need.
lrm is not set up to omit an intercept with the -1 notation.
My book goes into details about the continuation ratio model.
Frank Harrell
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