What is the purpose of the 'OUTPUT' statement in a DATA step?

The purpose of the 'OUTPUT' statement in a DATA step is to save the current observation to a dataset. When the DATA step is executed, it creates one or more observations based on the processing of the input data. By using the 'OUTPUT' statement, the programmer can explicitly control when to write an observation to the dataset being created.

This capability is particularly useful in scenarios where observations need to be written conditionally or when combining multiple output datasets. For example, a programmer might want to create two different datasets from the same input data conditionally; the 'OUTPUT' statement provides the flexibility to do this by specifying which observations to write to which dataset as they are processed.

In contrast, the other statements do not function as outlined: while the 'OUTPUT' statement does not display observations (as might be implied by the first option), it also does not inherently write reports or interrupt processing directly. The other options either misinterpret the functionality of the 'OUTPUT' statement or relate to different aspects of data processing in SAS.