Which elements are included in the PDV?

The Program Data Vector (PDV) is a critical concept in SAS that is used during the execution of a DATA step. It contains information about all the variables that are present during the processing of the DATA step, which includes both user-defined variables and system variables. System variables, such as N and ERROR, are automatically created by SAS and serve specific functions.

N keeps track of the number of iterations through the DATA step, while ERROR indicates whether an error has occurred during the data step's execution. Both of these system variables are essential for managing how the DATA step processes records and how to handle errors effectively. Therefore, the inclusion of system variables in the PDV is integral to the correct functioning of the DATA step, supporting the logic and flow of data manipulation tasks.

User-defined variables and input dataset variables can also reside in the PDV, but they are not the only components. The presence of system variables underscores the utility of the PDV in providing a comprehensive environment for data processing, making it clear that these variables play a fundamental role in the SAS DATA step execution process.