I use Proc PHREG to determine mortality rates with kaplan meier method.
My code is
proc phreg data=km_age1 ;
by age ;
output out=km_age1_sortie survival=sdf ;
My entry table contains the variable “age” (with only one age), the variable “t” for the truncation time, the variable “c” for the presence or not of censor and the variable “tps_survie” for the survival time.
Given that I am only one single age by entry table, I expected to have a single survival function estimation. However in exit, I have so much estimation as present individual at this age.
How to obtain a single estimation for this age ?
Is it necessary to classify the individuals in entry of this table?