I use the same structure and get error message. Could you please let me which part goes wrong in my code? Thanks a lot.   %macro loop_thru_fcat_list;     %local i next_name;     %let i=1;     %do %while (%scan(&fcat_name, &i) ne );        %let next_name = %scan(&fcat_name, &i);        %if not(&NEXT_NAME. in C1_EST FIBRINO) %then %do;           %cbs_fcat(&NEXT_NAME);        %end;        %let i = %eval(&i + 1);     %end; %mend loop_thru_fcat_list;   ERROR: A character operand was found in the %EVAL function or %IF condition where a numeric operand is required. The condition was: not(&NEXT_NAME. in C1_EST FIBRINO) ERROR: The macro LOOP_THRU_FCAT_LIST will stop executing. ... View more