[R] basehaz and newdata
mah
harwood262 at gmail.com
Mon Apr 7 17:34:55 CEST 2008
I am unable to get the basehaz function to apply a proportional
hazards model to a new data frame. I replicated my specific situation
with the example for coxph in the help, where I changed the x value of
the first record from 0 to 1. Is there something incorrect in the
syntax that I am using? Thanks in advance!
test1 <- list(time= c(4, 3,1,1,2,2,3),
status=c(1,NA,1,0,1,1,0),
x= c(0, 2,1,1,1,0,0),
sex= c(0, 0,0,0,1,1,1))
test2 <- list(time= c(4, 3,1,1,2,2,3),
status=c(1,NA,1,0,1,1,0),
x= c(1, 2,1,1,1,0,0),
sex= c(0, 0,0,0,1,1,1))
f1 <- coxph( Surv(time, status) ~ x + strata(sex), data=test1)
#stratified model
f2 <- coxph( Surv(time, status) ~ x + strata(sex), data=test2)
#stratified model
f1
Call:
coxph(formula = Surv(time, status) ~ x + strata(sex), data = test1)
coef exp(coef) se(coef) z p
x 1.17 3.22 1.29 0.907 0.36
Likelihood ratio test=0.87 on 1 df, p=0.351 n=6 (1 observation
deleted due to missingness)
> f2
Call:
coxph(formula = Surv(time, status) ~ x + strata(sex), data = test2)
coef exp(coef) se(coef) z p
x 0.896 2.45 1.42 0.63 0.53
Likelihood ratio test=0.38 on 1 df, p=0.535 n=6 (1 observation
deleted due to missingness)
>
> basehaz(f1, newdata=test2)
Error in basehaz(f1, newdata = test2) :
unused argument(s) (newdata = list(time = c(4, 3, 1, 1, 2, 2, 3),
status = c(1, NA, 1, 0, 1, 1, 0), x = c(1, 2, 1, 1, 1, 0, 0), sex =
c(0, 0, 0, 0, 1, 1, 1)))
>
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