Re: [EpiData-list] (no subject)

Hi. I cannot give you the comand syntax in epidata (maybe in Stata) but what you could simply do is the following: Create a variable first_visit_date = min(visit_date) by (id_unique) select where visit_date = firs_visit_date.

Serge

2014-09-29 14:41 GMT+02:00 epidata-list@lists.umanitoba.ca:

Dear ALL,

I have a data set where some patients have more than one entry (visit) i.e. same patient with different visit dates, while some have only one entry (visit). I would like to select only the first visit from each patient (The variables to use are id_unique and visit_date)

Regards

Walter _______________________________________________ EpiData-list mailing list EpiData-list@lists.umanitoba.ca http://lists.umanitoba.ca/mailman/listinfo/epidata-list