I would like to obtain a stratified baseline hazard in a Poisson regression model. What is the correct way to do it ?
Let A (=0/1) be the binary covariate on which I wish to stratify my baseline hazard, is it sufficient to write (in lme4, for example) :
glmer(event ~ interval*A + (1 + A|C), data=data,family=poisson, offset=log(time))
In this case, I got an estimate for a fixed coefficient for A0, but that does not interest me. It suggests to me that something is wrong with my formulation.
Any help ?