Re: [R] survival::survfit,plot.survfit

2009-03-03 Thread Terry Therneau
--- begin included message #Two models coxsst4 <- coxph(Surv(schaeden)~ S5, data=nino4) coxsst4_full <- coxph(Surv(schaeden)~ 0+S1+S2+S3+S4+S5+S6+S7+S8+S9+S10, data=nino4) #Set all covariates 0 attach(nino4) newS4 <- data.frame(S0=0., S1=0., S2=0., S3=0., S4=0., S5=0., S6=0., S7=0., S8=0.

Re: [R] survival::survfit,plot.survfit

2009-03-03 Thread Bernhard Reinhardt
You are right. In my case it doesn´t make much difference since the mean of my covariates is about 0. I made some more plots and again I´m confused. I thought when forcing all covariates via the newdata argument to be zero I would get the baseline function since the "linear predictor" is then

Re: [R] survival::survfit,plot.survfit

2009-02-27 Thread Heinz Tuechler
At 15:28 26.02.2009, Terry Therneau wrote: > plot(survfit(fit)) should plot the survival-function for x=0 or > equivalently beta'=0. This curve is independent of any covariates. This is not correct. It plots the curve for a hypothetical subject with x= mean of each covariate. Does this me

Re: [R] survival::survfit,plot.survfit

2009-02-26 Thread Jeff Xu
Thanks very much, Bernhard and Terry. It clarify my confusion and really helps a lot. Regards Jeff Xu Terry Therneau wrote: > >> plot(survfit(fit)) should plot the survival-function for x=0 or >> equivalently beta'=0. This curve is independent of any covariates. > > This is not correct. It

Re: [R] survival::survfit,plot.survfit

2009-02-26 Thread Terry Therneau
> plot(survfit(fit)) should plot the survival-function for x=0 or > equivalently beta'=0. This curve is independent of any covariates. This is not correct. It plots the curve for a hypothetical subject with x= mean of each covariate. This is NOT the "average survival" of the data set. Im

Re: [R] survival::survfit,plot.survfit

2009-02-26 Thread Bernhard Reinhardt
Jeff Xu wrote: I am confused when trying the function survfit. my question is: what does the survival curve given by plot.survfit mean? is it the survival curve with different covariates at different points? or just the baseline survival curve? for example, I run the following code and get the

[R] survival::survfit,plot.survfit

2009-02-25 Thread Jeff Xu
I am confused when trying the function survfit. my question is: what does the survival curve given by plot.survfit mean? is it the survival curve with different covariates at different points? or just the baseline survival curve? for example, I run the following code and get the survival curve