Are you sure your variables are categorical or numeric? Of course, glm differentiates these two kinds of variables. For example, I ran the same variable with different modes, the results are very different.
> dat<-data.frame(y=rpois(100,5),xf=as.factor(sample(1:4,100,replace=T))) > glm(y~xf,data=dat,family=poisson) Call: glm(formula = y ~ xf, family = poisson, data = dat) Coefficients: (Intercept) xf2 xf3 xf4 1.60944 -0.12783 -0.11878 -0.09746 ... > glm(y~as.numeric(xf),data=dat,family=poisson) Call: glm(formula = y ~ as.numeric(xf), family = poisson, data = dat) Coefficients: (Intercept) as.numeric(xf) 1.59047 -0.02673 Weidong Gu On Fri, Oct 28, 2011 at 4:21 PM, CES <smit4...@umn.edu> wrote: > Hey all, > > I am attempting to replicate my results achieved in another program within > R (so I can expand my options for methods). I am trying to run a GLM (Family > = Poisson) for count data in R. Some of my variables are factors and I am > under the impression that the function glm() cannot run a model with Poisson > dist and factors?? > > Here is why I think this, if I run two models using glm(), one treating a > variable (e.g., Harvest.Factor) as a Factor and the other treating a > variable as continuous (e.g., Harvest.Cont) I get the same results in R. > > Is there a package that will allow me to run a GLM using a Poisson dist and > factor variables? > > Thanks for any help! > -Chris > > > > > > -- > View this message in context: > http://r.789695.n4.nabble.com/GLM-Help-tp3949104p3949104.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > 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.