@ChrisBrooks "In your case there must be a value of either 1 or 5 as the first value in the data so agegroup has a length of 3 "   Variables get defined during the compilation phase and before data step iteration so what's in the data doesn't matter. The full reason for a length of 3 is, that this is the length of the first value assignment in the code:   then agegroup = '<30' ... View more