Create the numeric informat Evaluation. The INVALUE statement converts the specified values. The letters O (Outstanding), S (Superior), E (Excellent), C (Commendable), and N (None) correspond to the numbers 4, 3, 2, 1, and 0, respectively.

proc format;
   invalue evaluation 'O'=4
                      'S'=3
                      'E'=2
                      'C'=1
                      'N'=0;
run;