window push version 10.0
window push log using 8.8.2.Survival_to_PersonYears.log, replace
window push *  8.8.2.Survival_to_PersonYears.log
window push *
window push *  Convert survival data to person-year data.
window push *  The survival data set must have the following variables:
window push *      id      = patient id,
window push *      age_in  = age at start of follow-up,
window push *      age_out = age at end of follow-up,
window push *      fate    = fate at exit:  censored = 0, dead = 1,
window push *      treat   = treatment variable.
window push *
window push *  The person-year data set created below will contain one
window push *  record per unique combination of treatment and age.
window push *
window push *  Variables in the person-year data set that must not be in the
window push *  original survival data set are
window push *      age_now = an age of people in the cohort,
window push *      pt_yrs  = number of patient-years of observations of people
window push *                who are age_now years old, 
window push *      deaths  = number of events (fate=1) occurring in pt_yrs of 
window push *                follow-up for this group of patients.
window push *
window push use C:\WDDtext\8.8.2.Survival.dta, clear
window push list
window push generate exit = age_out + 1
window push stset exit, id(id) enter(time age_in) failure(fate)
window push stsplit age_now, at(0(1)6)
window push list  id age_in age_out treat fate exit age_now
window push sort treat age_now
window push collapse (count) pt_yrs=age_in (sum) deaths=fate, by (treat age_now)
window push list treat age_now pt_yrs deaths
window push save 8.8.2.Person-Years.dta, replace
window push log close