The Predict.Plot and TkPredict functions in the TeachingDemos package can also help with visualizing what the model means and the effect of the different terms.
-- Gregory (Greg) L. Snow Ph.D. Statistical Data Center Intermountain Healthcare greg.s...@imail.org 801.408.8111 > -----Original Message----- > From: r-help-boun...@r-project.org [mailto:r-help-boun...@r- > project.org] On Behalf Of Kjetil Halvorsen > Sent: Thursday, April 29, 2010 8:46 PM > To: Andrew Miles > Cc: r-help@r-project.org > Subject: Re: [R] Interaction terms in logistic regression using glm > > see comments below. > > On Wed, Apr 28, 2010 at 4:29 PM, Andrew Miles <rstuff.mi...@gmail.com> > wrote: > > I recently became aware of the article by Ai and Norton (2003) about > how > > interaction terms are problematic in nonlinear regression (such as > logistic > > regression). They offer a correct way of estimating interaction > effects and > > their standard errors. > > > > My question is: Does the glm() function take these corrections into > account > > when estimating interaction terms for a logistic regression (i.e. > when > > family=binomial)? > > No. > > If not, is there a function somewhere that allows for > > correct estimation? > > The estimation you get from glm is correct. The discussion in the > paper you referred > is about how to interpret the estimation results! A google search on > the referred paper > (you did'nt give the title), show up various later papers referring to > it, and not supporting their > conclusions. > > Linear (and non-linear) model books badly needs chapters with titles > such as "post-estimation analysis". glm does the estimation for you. > It cannot do the analysis for you! > > Probably you are looking for something such as CRAN package "effects". > > Kjetil > > > > > > > I've looked the documentation for glm and couldn't find an answer, > nor have > > I seen the issue addressed in the forums or in the examples of > logistic > > regression in R that I've found online. > > > > Thanks! > > > > Andrew Miles > > > > ______________________________________________ > > R-help@r-project.org mailing list > > https://stat.ethz.ch/mailman/listinfo/r-help > > PLEASE do read the posting guide http://www.R-project.org/posting- > guide.html > > and provide commented, minimal, self-contained, reproducible code. > > > > ______________________________________________ > R-help@r-project.org mailing list > https://stat.ethz.ch/mailman/listinfo/r-help > PLEASE do read the posting guide http://www.R-project.org/posting- > guide.html > and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.