2011/9/12 Göran Broström <goran.brost...@gmail.com> > Dear Ehsan, > > the cluster option is not implemented in 'eha', although you obviously get > no error if trying.... > I'll fix this. Thanks for the report. (So, use 'coxph' with cluster). > > Actually, there is nothing to fix; the cluster function works like the identity function. It's sole purpose is to mark a variable for special treatment when used in a call to a function from the survival package.
> Göran > > > On Mon, Sep 12, 2011 at 4:43 AM, Ehsan Karim <wilds...@hotmail.com> wrote: > >> Sorry: there was an error in the weight calculation, fixed version is >> the following, but still the final estimates differ as explained in >> the original email: >> >> >> ######################### >> >> require(survival) >> require(eha) >> >> data(heart) >> head(heart) >> >> follow <- heart$stop - heart$start >> fit <- glm(transplant ~ age + surgery + year + follow, >> data=heart, family = binomial) >> heart$wt <- ifelse(heart$transplant == 0, >> (1 - predict(fit, type = "response")), >> (predict(fit, type = "response"))) >> heart$iptw <- unlist(tapply(1/heart$wt, heart$id, cumprod)) >> summary(heart$iptw) >> >> # no weights >> fit0 <- coxph(Surv(start,stop,event)~transplant, data=heart) >> fit0 # fit with coxph without case-weights >> fit1 <- coxreg(Surv(start,stop,event)~transplant, data=heart) >> fit1 # fit with coxreg from eha without case-weights >> >> # coxph >> fit2 <- coxph(Surv(start,stop,event)~transplant + cluster(id), >> data=heart, weights = iptw, robust = T) >> fit2 # fit with coxph having robust and cluster option >> fit3 <- coxph(Surv(start,stop,event)~transplant + cluster(id), >> data=heart, weights = iptw) >> fit3 # fit with coxph having cluster option >> fit4 <- coxph(Surv(start,stop,event)~transplant, >> data=heart, weights = iptw) >> fit4 # fit with coxph >> >> # coxreg >> fit5 <- coxreg(Surv(start,stop,event)~transplant + cluster(id), >> data=heart, weights = iptw) >> fit5 # fit with coxreg from eha having cluster option >> fit6 <- coxreg(Surv(start,stop,event)~transplant, >> data=heart, weights = iptw) >> fit6 # fit with coxreg from eha >> >> exp(coef(fit3)) # HR from coxph having cluster option >> exp(coef(fit4)) # HR from coxph >> exp(coef(fit5))[1] # HR from coxreg having cluster option >> exp(coef(fit6))[1] # HR from coxreg >> >> ######################### >> > exp(coef(fit3)) # HR from coxph having cluster option >> transplant1 >> 17.94681 >> > exp(coef(fit4)) # HR from coxph >> transplant1 >> 17.94681 >> > exp(coef(fit5))[1] # HR from coxreg having cluster option >> transplant1 >> 20.06519 >> > exp(coef(fit6))[1] # HR from coxreg >> transplant1 >> 17.94681 >> ######################### >> >> ______________________________________________ >> 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. >> > > > > -- > Göran Broström > > -- Göran Broström [[alternative HTML version deleted]]
______________________________________________ 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.
