What must always follow every step in a SAS program?

In SAS programming, it is essential to conclude every step with either a run statement, a quit statement, or the initiation of a new step. This requirement is rooted in the syntax and structure of SAS procedures.

A run statement indicates to the SAS system that the current step or procedure is complete and the results should be processed. Without a run statement, specified procedures might not execute, leading to incomplete or missing outputs. A quit statement serves a similar purpose, particularly for procedures that require it to exit that specific procedure without further interaction. Additionally, starting a new step with a data step or a procedure also signals to the system that the previous step has been finalized.

In contrast, other options, while important in certain contexts, do not serve the foundational requirement of completing SAS steps. Comments are useful for documentation but are not obligatory at the end of every step. Title statements enhance the output but are not necessary for program execution. Data validation commands are valuable for checking data integrity but are not a structural requirement for every step in SAS programming.