What should you use if you are evaluating a calculated variable in a dataset?

When evaluating a calculated variable in a dataset, using an IF statement is essential because it allows for conditional logic to be applied directly to the data during data step processing. The IF statement can be utilized to perform operations that depend on the value of the calculated variable, enabling you to create new variables or filter records based on specific conditions.

For instance, if you have a calculated variable that represents a score based on certain metrics, you can use an IF statement to classify that score into categories, such as 'Pass' or 'Fail', or to apply any form of transformation or decision-making logic based on its value. This versatility makes the IF statement particularly powerful for data manipulation and conditional processing within the data step.

In contrast, the other options serve different purposes: the SELECT statement is primarily used in SQL procedures, the WHERE statement filters observations in datasets but does not evaluate calculated values during data step execution, and the MERGE statement combines datasets rather than evaluating or transforming individual variable values.