If these are the only messages, you don't have to do anything.  Your data is fine as is.  The messages are annoying but not critical.   The issue is this.  When a numeric field contains "NULL", what do you want SAS to do?  Well, if the variable is to be numeric, SAS can't store "NULL" as the value.  SAS changes it to a missing value instead, which is a decent outcome.  Did you have a different outcome in mind?   Check a few lines that generated these messages, and see if you are happy with the result. ... View more