Hi,   Regardless the fact that you didn't initialized variables, as @ballardw pointed out, reasons seems to be as follows:   a) - double semicolon after "if-then" part - it should be 1 (one) semicolon there, with two(;;) sas thinks that you have an empty statement there (second semicolon) and it throws an syntax error on the "else" part    b)  - as @ballardw pointed out, Label is not execution time statement but compilation time one. Try to test following code (which from the execution time point of view reduces to "empty" do-end block): data _null_; if a >= b then do; label dob="date of birth"; end; else do; label dob="date of death"; end; run; all the best Bart     ... View more