Define the first range in the BENEFIT. format. This first range differentiates between the employees who were hired on or before 31DEC1979 and those who were hired after that date. The keyword LOW and the SAS date constant '31DEC1979'D create the first range, which includes all date values that occur on or before December 31, 1979. For values that fall into this range, SAS applies the WORDDATEw. format. (footnote 1)

      value benefit  low-'31DEC1979'd=[worddate20.]

FOOTNOTE 1:  For more information about SAS date constants, see the section on dates, times, and intervals in SAS Language Reference: Concepts. For complete documentation on WORDDATEw., see the section on formats in SAS Language Reference: Dictionary.