Re: st: R: Estimating the probability of censoring

[Michael McCulloch <mm@pinest.org>]

> at a very first glance, what hits the eyes is the adjusted probability of
> being censoring sometimes above the usual upper constraint. How can it be? I
> should have missed something in your assumptions.
Yes, that's one of my main questions. Since I 
used the Stata-supplied cancer.dta file and 
provided all my methods, I'm hoping that someone 
on Statalist might have advice on how to correct 
the method for unadjusted estimation of censoring 
probability.




> Kind Regards,
> Carlo
>
>
> -----Messaggio originale-----
> Da: owner-statalist@hsphsun2.harvard.edu
> [mailto:owner-statalist@hsphsun2.harvard.edu] Per conto di Michael McCulloch
> Inviato: gioved� 25 settembre 2008 17.56
> A: Statalist
> Oggetto: st: Estimating the probability of censoring
>
> Hello,
> I'm seeking guidance on a series of commands I've written to estimate
> the probability of being censored. Might anyone be able to offer
> commentary as to whether I've done this correctly?  The resulting
> unadjusted probability of censoring ranges from 0-1, while the
> adjusted probability goes above 1.
>
> sysuse cancer.dta, clear
> gen id = _n				//  generate individual IDs
> stset studytime, failure(died==0)		//  note that total
> person-time is 744
> *estimate the unadjusted probability of censoring
> sts gen cens = s
> *estimate the adjusted probability of censoring
> stcox drug age, nohr
> predict coeff_cens, xb			// predicts linear
> coefficients of censoring
> gen p_cens = exp(coeff_cens)		// adjusted probability of
> time-to-censoring
> *lists the results
> list id drug age died cens p_cens in 40/48, clean noobs
>
> 40	3	50	0	.58476475	.8601028
> 41	3	55	1	.58476475	.9429854
> 42	3	57	1	.51166915	.9783332
> 43	3	48	0	.51166915	.8290267
> 44	3	56	0	.34111277	.9604967
> 45	3	60	1	.34111277	1.033855
> 46	3	62	0	.22740851	1.072609
> 47	3	48	0	.11370426	.8290267
> 48	3	52	0	0	.8923438
>
> --
>
> Best wishes,
> Michael McCulloch
>
>
>
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