Dear Stata Users,
let me add a hint to previous Veit's posting:
If you have a dataset that already encompasses all cases and a sub-cohort
of your total population than you "translate" the SAS program (relevant
extract from the above webpage below) into Stata.
Some User pointed me this problem in using stcascoh: We already have a
sample of original cohort and all cases. So how we can use stcascoh to
prepare dataset for further analysis without sampling from cohort?
There is a trick.
We must have two files: a subcohort data file and a distinct data file for
non-subcohort cases.
1) Let we start using subcohort data
use subcohort.dta
stset timevar, f(failvar) ecc. -> stset data before using stcascoh
stcascoh, a(.9999) ---> All members of subcohort are sampled and
processed by stacascoh
save mycohort
2) Then use non-subcohort data
use casefile.dta,clear
stset timevar, f(failvar) ecc. -> stset data as before in subcohort.dta
stcascoh, a(0) ---> All cases are included and processed as non subcohort
cases by stacascoh
3) append two files
append using mycohort
That's all.
So Stata Users have not the trouble to "translate" a SAS program.
They can simply use stcascoh with fewest further commands to reach all that
they need.
Enzo
////////////////
Enzo Coviello, MD
Az. USL BA/1
via Barbera 27 - 70055 MINERVINO MURGE (Ba)
Italy
tel +39 0883 691053
fax +39 0883 691053
tel (home) +39 0883 695055
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