What happens when multiple INPUT statements are used in a DATA step?

When multiple INPUT statements are used in a DATA step, it allows the program to read data from different types of records or files into the same dataset. Each INPUT statement can be tailored to read a specific format or structure of the data, making it possible to handle various types of observations in a structured way.

For instance, if a data set contains records that have different structures or formats, multiple INPUT statements enable the programmer to define how each part of the data should be read. Consequently, this supports the flexibility needed when dealing with complex datasets where some records may have additional variables or different delimiters.

This capability enhances the robustness of the DATA step, ensuring that diverse data can be read into a single output dataset properly. It is important to note that while each INPUT statement can read from different records, the observations must be structured properly in the data source for the DATA step to create a coherent dataset.