In a DATA step, what is the outcome of using the SET statement?

The SET statement in a DATA step is used to read in existing datasets, thereby allowing you to process the data. When you utilize the SET statement, it combines datasets vertically, meaning that it appends the observations from one dataset to another. This is particularly useful when you have multiple datasets containing similar variables and want to create a single dataset that includes all observations from the individual datasets.

When you use the SET statement, SAS reads each observation from the specified dataset(s) in the order they are provided and includes them into the new dataset being created. This functionality makes it straightforward to merge datasets of the same structure while maintaining the integrity of the original data.

It's important to note that while the SET statement does not directly update existing observations, create new variables, or sort data, it does serve as a foundational command for combining datasets effectively, making it a critical component of data manipulation in SAS.