# st: HOW TO RETRIEVE TIME-SPECIFIC BASELINE AND PREDICTED SURVIVALFIGURES?

 From "Brian Harrison" To statalist@hsphsun2.harvard.edu Subject st: HOW TO RETRIEVE TIME-SPECIFIC BASELINE AND PREDICTED SURVIVALFIGURES? Date Mon, 08 Oct 2007 16:53:17 +0100

Dear All,

I wonder if you could help me with the following query. I have been trying to retrieve time-specific baseline and predicted survival figures (and their 95%CI) after fitting a Cox model including a three-level categorical variable using the following commands:
stcox x2 x3 ,bases(BS) (where x2 and x3 are dummy variables derived from x)
gen predx2=BS^exp(_b[x2]) if x2==1
gen predx2_L = BS^exp(-1.96*_se[x2]) if x2==1
gen predx2_U = BS^exp(1.96*_se[x3]) if x2==1
gen predx3=BS^exp(_b[x3]) if x3==1
gen predx3_L = BS^exp(-1.96*_se[x3]) if x3==1
gen predx3_U = BS^exp(1.96*_se[x3]) if x3==1

I have two difficulties here:
First, I do not know how I could retrieve the 95%CI estimates for the baseline survival.
Second, I do not know how to retrieve the baseline and predicted survival (and 90%CI) figures for specific survival times (e.g. 90 days, 1 year etc). In other words, is it possible to obtain a list of the time-specific baseline and predicted survival figures and their 95%CI in the same way the Kaplan-Meier survivor function could be retrieved for different survival times (using the command sts list,at(90,365))?

Many thanks for your help.

Brian Harrison

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