This section provides an overview of how project information is stored in the SAS System in data sets and how these data sets are used by the CPM, GANTT, NETDRAW, and PM procedures. Maintaining the project information in SAS data sets enables you to merge project information easily from several sources, summarize information, subset project data, and perform a wide variety of other operations using any of the many procedures in SAS software. Each of the SAS/OR procedures also defines a SAS macro variable that contains a character string indicating whether or not the procedure terminated successfully. This information is useful when the procedure is one of the steps in a larger program.