What is the function of the OUTPUT statement in a DATA step?

The OUTPUT statement in a DATA step serves the essential function of specifying the data set to which observations are written. When this statement is included, it allows the programmer to control the flow of data output to specific datasets or even to multiple datasets. Each time the OUTPUT statement is invoked within a DATA step, the current observation is sent to the specified dataset.

This flexibility is particularly useful when you want to create different datasets from a single DATA step based on certain conditions or calculations made during the execution of the step. For instance, if you are processing raw data that needs to be split into various groups or categories, the OUTPUT statement makes it easy to direct observations into the appropriate dataset depending on the criteria you have established in your code.

In direct contrast, the other options highlight different functionalities that do not apply to the OUTPUT statement. For instance, defining the location for an output report or summarizing data involves different procedures or statements altogether. Filtering observations relates more to the IF or WHERE statements, which are used to conditionally include or exclude observations based on specific criteria at the time of data processing.