Something like: DATA DIFF0 DIFF1 DIFF2 DIFF3 DIFF4 DIFF5 DIFF6 DIFF7; SET PATEVENT(KEEP=PATID EVENTDAT); BY PATID EVENTDAT; RETAIN PREVDATE; IF FIRST.PATID THEN PREVDATE=EVENTDAT; ELSE SELECT(EVENTDAT-PREVDATE); WHEN(0) OUTPUT DIFF0; WHEN(1) OUTPUT DIFF1; ... OTHERWISE; END; RUN;

Then SORT NODUPKEY by PATID to remove duplicates. NOTE: EVENTDAT is not required in the BY statement in the main datastep--I just coded it so that mis-sorted files would generate an error. Cheap insurance.

Tim Berryhill - Contract Programmer and General Wizard TWB2@PGE.COM or http://www.aartwolf.com/twb.html Frequently at Pacific Gas & Electric Co., San Francisco The correlation coefficient between their views and my postings is slightly less than 0 ----------------------[Reply - Original Message]---------------------- I have a number of patients with a number of event dates. I would like to create datasets with patients who have more than one event at the same date, more than one event within 1, 2, 3, 4, 5, 6, 7 days.