Thanks for your reply. Here is the error as it appears in the log: 8 proc descript data = demo_f filetype = sas design = wr; ---- 22 76 NOTE: An external program, not a SAS procedure, is being executed. ERROR 22-322: Syntax error, expecting one of the following: ;, AUDIT, CC, CLEANUP. ERROR 76-322: Syntax error, statement will be ignored. 9 weight wtint2yr; 10 nest sdmvstra sdmvpsu / missunit; 11 var ridageyr; 12 run; NOTE: The SAS System stopped processing this step because of errors. NOTE: PROCEDURE DESCRIPT used (Total process time): real time 0.01 seconds cpu time 0.01 seconds I've tried restarting SAS and running others' code to check that it wasn't just an error with my code, but I keep getting the same message, regardless.  ... View more