[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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