[R] Baseline survival estimate

[tlumley at u.washington.edu]

survival = exp(-hazard)

      -thomas

On Wed, 16 Dec 2009, Laura Bonnett wrote:

> Dear R-help,
>
> I am trying to obtain the baseline survival estimate of a fitted Cox model
> (S_0 (t)).  I know that previous posts have said use 'basehaz' but this
> gives the baseline hazard function and not the baseline survival estimate.
> Is there a way to obtain the baseline survival estimate or do I have to use
> the formula which does something like S(t) = exp[- the integral from 0 to t
> of h(u) du]?
>
> Thank you for your assistance,
>
> Laura
>
> fit1 <-
> coxph(Surv(tsecond/365,seccens)~stroke(smess1)+othnd(smess1)+relat(smess1)+asleep(smess1)+abeeg1(smess1)+treat(smess1),data=smess1)
> basehaz(fit1)
>
> where stroke is a function which creates a binary variable from the dataset
> smess1 etc.
>
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>
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Thomas Lumley			Assoc. Professor, Biostatistics
tlumley at u.washington.edu	University of Washington, Seattle