I've always thought of it as:

"If you use more than one SET statement in a data step, the results are unpredictable and you get what you deserve." I've always avoided that method and looked for alternative ways, simply because of the unpredictable results.

The exception being the "IF _N_=1 THEN SET ;" statement. You can view an online presentation (MS-Power Point required) at http://www.spikeware.com/ftp/ppt/sw005.ppt. Perhaps this can shed some light on the subject.

Paul D. McDonald pdm@spikeware.com SPIKEware, Inc. ----------------------------- Free SAS Training downloads and SAS Newsletter http://www.spikeware.com/