Some SAS procedures, such as PROC REG and PROC GLM, support RUN-group processing, which means that a RUN statement does not end the procedure. A QUIT statement explicitly ends such procedures. If you omit the QUIT statement, a PROC or a DATA statement implicitly ends such procedures. When you use ODS with procedures that support RUN-group processing, it is good programming practice to specify a QUIT statement at the end of the procedure. This causes ODS to clear the selection or exclusion list, and you are less likely to encounter unexpected results.