[R] Models for Discrete Choice in R

[Frank E Harrell Jr]

Emmanuel Charpentier wrote:
> Le dimanche 08 novembre 2009 à 17:07 -0200, Iuri Gavronski a écrit :
>> Hi,
>>
>> I would like to fit Logit models for ordered data, such as those
>> suggested by Greene (2003), p. 736.
>>
>> Does anyone suggests any package in R for that?
> 
> look up the polr function in package MASS (and read the relevant pages
> in V&R4 and some quoted references...) or the slightly more
> sophisticated (larger range of models) lrm function in F. Harrell's
> Design (now rms) packge (but be aware that Design is a huge beast witch
> carries its own "computing universe", based on (strong) Harrell's view
> of what a regression analysis should be : reading his book is, IMHO,
> necessary to understand his choices and agree (or disgree) with them).
> 
> If you have a multilevel model (a. k. a. one "random effect" grouping),
> the "repolr" packge aims at that, but I've been unable to use it
> recently (numerical exceptions).
> 
>> By the way, my dependent variable is ordinal and my independent
>> variables are ratio/intervalar.
> 
> Numeric ? Then maybe some recoding/transformation is in order ... in
> which case Design/rms might or might not be useful.

I'm not clear on what recoding or transformation is needed for an 
ordinal dependent variable and ratio/interval independent variables, nor 
why rms/Design would not be useful.

Frank

> 
> HTH,
> 
> 					Emmanuel Charpentier


-- 
Frank E Harrell Jr   Professor and Chair           School of Medicine
                      Department of Biostatistics   Vanderbilt University