@YD5265 Adding an explanation to why you got the results you did, prior to implementing @PaigeMiller solution. There are two types of Data Step statements, Declarative & Executable The first 5 lines (up to and including length CNS_P_LBL $16;) are all declarative, the rest executable. Executable statements are processed in the order they appear in the data step. Your first executable statement is  if CNS_P_LBL = "1971-1990" then YEARBUILT = "01/01/1971"; At this point in the data step execution CNS_P_LBL (as is YEARBUILT) is an empty string, it is a known variable as it was declared in the length statement during the compilation phase.  None of your IF statements are true when CNS_P_LBL is an empty string so YEARBUILT will be an empty string.  When the execution phase reaches the set INPUT; statement, then CNS_P_LBL is read from the INPUT data set, resulting in its value being set to 1971-1990. An easy way to see this to understand it, is to use PUT statements within your code (note this is a handy debugging method): data OUTPUT; length YEARBUILT $100; format YEARBUILT $100.; informat YEARBUILT $100.; length CNS_P_LBL $16; PUT "1) " _all_ ; /* _all_ will output all the variable values */ if CNS_P_LBL = "1971-1990" then YEARBUILT = "01/01/1971"; if CNS_P_LBL = "1991-2000" then YEARBUILT = "01/01/1990"; if CNS_P_LBL = "2001-2005" then YEARBUILT = "01/01/2003"; if CNS_P_LBL = "2006-2010" then YEARBUILT = "01/01/2008"; if CNS_P_LBL = "2011-2015" then YEARBUILT = "01/01/2013"; if CNS_P_LBL = "2016-2020" then YEARBUILT = "01/01/2018"; if CNS_P_LBL = "1970 or before" then YEARBUILT = "12/31/9999"; PUT "2) " _all_ ; /* _all_ will output all the variable values */ set INPUT; PUT "3) " _all_ ; /* _all_ will output all the variable values */ RUN ; Paige's solution works, because once you move the SET statement prior to the IF statements, then the variable CNS_P_LBL gets assigned prior to the IF statements.     ... View more