Hi all, I have some questions about the predicted HR in coxph function including psline covariate.
If just fitting covariate as linear form, by default, the reference value for each of predictions type (linear predictor, risk and terms) is the mean covariate within strata. If the psline is specified for the covariate, what's the reference value for the predictions? I did some test code below: ### par(mfrow = c(1,3)) test = coxph(Surv(time, status) ~ age, cancer) test2 = coxph(Surv(time, status) ~ pspline(age, df=2), cancer) test3 = coxph(Surv(time, status) ~ pspline(age, df=5), cancer) pptest3=predict(test3, type="lp") pptest2= predict(test2, type="lp") pptest = predict(test, type="lp") plot(cancer$age, exp(pptest)) abline(v=mean(cancer$age)) abline(h=1) plot(cancer$age, exp(pptest2)) abline(v=mean(cancer$age)) abline(h=1) plot(cancer$age, exp(pptest3)) abline(v=mean(cancer$age)) abline(h=1) In the first model, age is just fitted as linear, and in the plot, when HR =1 when age equals to the mean of age. However, it's not the case when age is fitted as using psline. So what are the reference value of age when psline is used? Any help or idea will be very much appreciated! Best, Carrie-- [[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.