As you suggested I had a further look at the profile by changing default values of stepsize (I tried to modify the others but apparently there was any change). Here they go the scripts I have used:
> dati<-read.table("simone.txt",header=T,sep="\t",as.is=T) > glm.sat<-glm(sex~twp+hwp+hcp+hnp,binomial,data=dati) Mensajes de aviso perdidos glm.fit: fitted probabilities numerically 0 or 1 occurred >pp<-profileModel(glm.sat,quantile=qchisq(0.95,1),objective="ordinaryDeviance",which=4) Preliminary iteration . Done Profiling for parameter hcp ... Done >pp1<-profileModel(glm.sat,quantile=qchisq(0.95,1),objective="ordinaryDeviance",which=4,stepsize=20) Preliminary iteration . Done Profiling for parameter hcp ... Done >pp2<-profileModel(glm.sat,quantile=qchisq(0.95,1),objective="ordinaryDeviance",which=4,stepsize=100) Preliminary iteration . Done Profiling for parameter hcp ... Done >plot(pp) >mtext("Default stepsize",adj=0,cex=2,line=1) >dev.new() >plot(pp) >mtext("Stepsize=20",adj=0,cex=2,line=1) >dev.new() >plot(pp) >mtext("Stepsize=100",adj=0,cex=2,line=1) And these are the plots as they look like: http://r.789695.n4.nabble.com/file/n3904261/plot1.png http://r.789695.n4.nabble.com/file/n3904261/plot2.png http://r.789695.n4.nabble.com/file/n3904261/plot3.png I have tried to understand what is going on but I don't know how to interpret this. It's quite a long time that I am trying to solve this but I have not been able to. Here ( http://r.789695.n4.nabble.com/file/n3904261/simone.txt simone.txt ) I attach a subset of the data I am working with that comprises the variables specified in the above glm model and by the way the "funky" variable called "hcp". Thank you for take your time to help me in this. -- View this message in context: http://r.789695.n4.nabble.com/binomial-GLM-quasi-separation-tp3901687p3904261.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.