# st: RE: Breslow baseline hazard estimator of Cox.

 From "Stephen P Jenkins" To Subject st: RE: Breslow baseline hazard estimator of Cox. Date Tue, 13 Apr 2004 09:35:48 +0100

```> -----Original Message-----
> From: owner-statalist@hsphsun2.harvard.edu
> [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of
> gong shizhuo
> Sent: 13 April 2004 03:09
> To: statalist@hsphsun2.harvard.edu
> Subject: st: Breslow baseline hazard estimator of Cox.
>
> Dear Stata Users:
>
> Does anyone know how to estimate the Breslow baseline hazard
> estimators of
> Cox model using Stata? Or SAS, R?

In Stata, you can estimate a Cox proportional hazard model for
continuous survival time data with -stcox- using any of 4 methods of
handling ties (breslow, efron, exactm, exactp). Using the appropriate
options, you can have -stcox- calculate the baseline cumulative hazard
function, the baseline survivor function, and the baseline hazard
contribution.  Note that the last of these refers to the hazard
/contribution/. You can't estimate a hazard function per se.  [Recall
that the continuous time hazard rate h(t) is equal to [-dS(t)/dt]/S(t)
for survivor function S(t), or the derivative of the cumulative hazard
function H(t). But the estimates of S(t) and H(t) are step functions of
observed survival times, and so slopes -- and hence hazards -- are not
well-defined.]  You can calculate a /smoothed/ hazard function, however.

For further details, have a look at Manual [ST], and Cleves et al. /An
Introduction to Survival Analysis using Stata/.

Stephen
-------------------------------------------------------------
Professor Stephen P. Jenkins <stephenj@essex.ac.uk>
Institute for Social and Economic Research
University of Essex, Colchester CO4 3SQ, U.K.
Tel: +44 1206 873374.  Fax: +44 1206 873151.
http://www.iser.essex.ac.uk

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```