What is the purpose of the INPUT statement in a DATA step?

The INPUT statement in a DATA step serves the primary purpose of identifying the order in which the values of data lines are read into SAS variables. It specifies how to read raw data into the program by defining the format of the input data. When processing data from external files or inline data, the INPUT statement determines which columns of the data correspond to which variables in the SAS dataset.

This is crucial for correctly assigning values to variables; for example, if multiple values are present on a single line of data, the INPUT statement allows you to specify how these values should be separated and understood by SAS.

While generating reports and printing datasets are important aspects of data analysis, those activities occur after data has been successfully read and processed. Similarly, validating data types is a step that may happen later in the process as data is manipulated and analyzed. The INPUT statement's chief role is to establish the initial structure of the dataset by defining how input data is read and interpreted.