st: Survival function of regression Cox model postestimation

[petretta@unina.it]

Hello,

I use STATA/IC 11.2 for Windows XP.

I ask for an explanation on Cox survival post-estimation.
I know that the baseline survival function of the Cox model without  
covariates is the same as the Kaplan Meier survival function.
However, it is unclear for me why the survival function of a Cox model  
with covariates obtained at the mean values of the covariates is  
different from baseline survival function of the Cox model without  
covariates.

I hope I made myself clear.

Thanks for your consideration


Mario Petretta
Dipartimento di Medicina Clinica Scienze Cardiovascolari e Immunologiche
Facoltà di Medicina e Chirurgia
Università di Napoli Federico II
081 - 7462233


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