How can one create a new variable in a DATA step?

Creating a new variable in a DATA step can be accomplished by assigning a value using an assignment statement. This process involves defining a new variable and specifying its value directly within the DATA step code. For instance, you could write something like new_variable = existing_variable + 10; to create new_variable based on the value of existing_variable.

This method is straightforward and allows for flexible calculations and transformations of the data in the same DATA step. It is particularly useful when the variable is derived or calculated from existing variables in a single pass of the data.

Other methods listed, like using the SET statement, typically do not create new variables but rather read existing variables from a dataset. While PROC SQL has its own syntax for managing data, which can include creating new variables, it is not specific to the DATA step context. Merging with another dataset can create new variables if they are introduced through that merge; however, this involves additional complexities and is not as direct as utilizing an assignment statement within a DATA step.