Well your approach does exactly what I wanted!   The window does still open, but it's minimized by default. The messages still print too. ... View more

That does the trick, thanks! ... View more

Ah okay, you meant those work files pertaining to a particular macro call should be deleted when the program has finished using them. Good point. Sorry, I was thinking only of the clean-up at the end of the SAS session. ... View more

I definitely need to learn more about when macros resolve to "text" and when they resolve to "executetable code". Your example helps with that understanding. Thanks!     ... View more

Thank you!   This is exactly what I need. ... View more

Thank you all for responding.   In light of the added complexity, I'll just use the OR operator ....but it's good to know how properly use the IN() operator if needed in the future! A requirement of this particular macro is maintainability by "non SAS experts" hence it would be inappropriate to rely on options or other such dependencies.     %MACRO CONVERTOR (CONVERSION_TYPE = ); %IF &CONVERSION_TYPE = MILES_TO_METERS OR &CONVERSION_TYPE = MILES_TO_FEET %THEN %DO; %LET ORIGINAL_UNIT = MILES; %END; %MEND; %CONVERTOR (CONVERSION_TYPE = MILES_TO_METERS);   ... View more

Thank you very much - your solution is much better than mine! ... View more

Thank you for the quick reply!   I think these two techniques will do the trick. ... View more