[R] Probabilities from survfit.coxph:

[Joris Meys]

On Wed, Jun 23, 2010 at 9:03 PM, Parminder Mankoo <pkmankoo09 at gmail.com> wrote:
> Hello:
>
> In the example below (or for a censored data) using survfit.coxph, can
> anyone point me to a link or a pdf as to how the probabilities appearing in
> bold under "summary(pred$surv)" are calculated? Do these represent
> acumulative probability distribution in time (not including censored time)?

predicted survival. Hence the column name "survival"...

Cheers
Joris
>
> Thanks very much,
> parmee
>
> *fit <- coxph(Surv(futime, fustat) ~ age, data = ovarian)*
> *pred <- survfit(fit, newdata=data.frame(age=60))*
> *summary(pred)*
>
>  time n.risk n.event survival std.err lower 95% CI upper 95% CI
>   59     26       1    *0.978*  0.0240        0.932        1.000
>  115     25       1    *0.952*  0.0390        0.878        1.000
>  156     24       1    *0.917*  0.0556        0.814        1.000
>  268     23       1    *0.880*  0.0704        0.752        1.000
>  329     22       1    *0.818*  0.0884        0.662        1.000
>  353     21       1    *0.760*  0.0991        0.588        0.981
>  365     20       1    *0.698*  0.1079        0.516        0.945
>  431     17       1    *0.623*  0.1187        0.429        0.905
>  464     15       1    *0.549*  0.1248        0.352        0.858
>  475     14       1    *0.480*  0.1267        0.286        0.805
>  563     12       1    *0.382*  0.1332        0.193        0.757
>  638     11       1    *0.297*  0.1292        0.127        0.697
>
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>
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-- 
Joris Meys
Statistical consultant

Ghent University
Faculty of Bioscience Engineering
Department of Applied mathematics, biometrics and process control

tel : +32 9 264 59 87
Joris.Meys at Ugent.be
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