Emmanuel Charpentier wrote:
Le dimanche 08 novembre 2009 ? 17:07 -0200, Iuri Gavronski a ?crit :
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.