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;