clear all
set memory 200M
cd e:\chililabdata\data

global refdate = mdy(7,1,$year)
use individres
drop if (res_edate != . & res_edate < $refdate)
drop if (res_sdate != . & res_sdate > $refdate)
keep individid  locationid
duplicates drop individid, force
sort individid 
save cross\crossindividres, replace
use observation
sort observeid
save observation, replace

use membership
drop if (mem_edate != . & mem_edate < $refdate)
drop if (mem_sdate != . & mem_sdate > $refdate)
duplicates drop individid, force
rename mem_sobserveid observeid 
sort observeid
merge observeid using observation
tab _merge
drop if _merge !=3
drop _merge
rename locationid sociallocid
gen communeid = substr(sociallocid, 1,2)
sort individid

merge individid using cross\crossindividres
table _merge
drop _merge
gen isresident =0
replace isresident =(locationid==sociallocid)
drop if isresident == $isresident
replace communeid="00" if $communeid ==0
drop if communeid ! ="0$communeid" 
sort communeid
collapse  (count) midyearpop=mem_episodeid, by (communeid)
keep communeid  midyearpop 
sort communeid
save cross\MidYearPop, replace
cd e:\chililabdata