[R] basehaz and newdata

[Roland Rau]

Hi,

just looked at it briefly and I don't know if it is the real cause for 
your problems. But 'data' as well as 'newdata' require a data.frame and 
not a list as input.

Does this help?

Best,
Roland


mah wrote:
> 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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