<>
I am betting that you want a count of visits, not a running sum, but correct
me if I am wrong...
*************
clear*
set obs 400
egen float patient = seq(), from(1) to(400) block(4)
egen float visit = seq(), from(1) to(4) block(1)
//not strictly necessary
xtset patient visit
//less than 4 visits for some
replace visit =. if runiform()<0.05
bys patient: egen overallvisits=count(visit)
l in 1/20, sepby(patient) noo
*************
HTH
Martin
-----Ursprüngliche Nachricht-----
Von: [email protected]
[mailto:[email protected]] Im Auftrag von Shehzad Ali
Gesendet: Mittwoch, 15. April 2009 16:48
An: [email protected]
Cc: [email protected]
Betreff: st: simple sum() question
Hi,
I have a simple question about summing across observations. I have 100
patients (variable: patient_id) in the dataset, each had clinic visits
(variable: clinic) and hospital visits (variable: hospital) recorded at
weeks 4, 8, 12 and 16. The dataset is long and hence I have 400
observations (one observation per patient per time point).
I want to sum the clinic visits for each patient (across all 4 visits)
bearing in mind that some patients had less than 4 visits. So effectively I
want to generate a new variable that will produce the sum of clinic visits
for each patient.
Any help would be appreciated.
Thank you,
Shehzad
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