Assuming you want to compare fill date to previous record end date.  Use a retain variable in your data step.   data laterefills;   set exampledata;   by ID;   retain last_end_dt .;   if first.id then call missing(last_end_dt);   if fill_dt>last_end_dt and first.id=0 then output;   last_end_dt=end_dt; run; ... View more