Question

Which statement about DROP= and KEEP= data set options is true?

a. The options apply to all output data sets created in the DATA statement
b. Using the options with input data affects the content of the program data vector.
c. When the options are used in the same DATA step that includes a DROP or KEEP statement, the options are applied first.
d. If you don't need all the variables in your input data for processing, it's most efficient to eliminate them using one of these data set options in the DATA statement.

Answer 1

The true statement about DROP= and KEEP= data set options is that it's most efficient to eliminate variables you don't need in processing by using one of these options in the DATA statement.

Step-by-step explanation:

The statement about DROP= and KEEP= data set options that is true is: d. If you don't need all the variables in your input data for processing, it's most efficient to eliminate them using one of these data set options in the DATA statement. This statement is true because specifying the DROP= or KEEP= data set options in the DATA statement allows you to specify which variables you want to drop or keep from the data set right at the beginning of the data step processing.

This means that SAS does not have to read and store the unwanted data in the Program Data Vector (PDV), which can save resources and improve performance when working with large data sets. Moreover, using the DROP= or KEEP= options can also help make the code cleaner and easier to understand, as only the relevant variables are included.