When merging two data sets with the MERGE statement, how is it possible to filter observations based on a variable condition?

When merging two data sets using the MERGE statement, it is indeed possible to filter observations based on a variable condition. Utilizing both the IF statement and the WHERE clause allows for flexible control over which observations to include in the final dataset.

By placing an IF statement after the MERGE statement, you can specify conditions that the merged observations must meet in order to be written to the output dataset. This means that only those observations that satisfy the given condition will be processed further.

On the other hand, using a WHERE clause before the MERGE statement can also restrict the data being merged based on specified conditions. The WHERE clause filters the data sets before they are merged, meaning only relevant records from each data set are brought together based on the specified condition.

Therefore, both the IF statement used after merging and the WHERE clause used before merging provide viable methods for filtering observations. Hence, selecting both options reflects a comprehensive approach to managing the dataset during the merge operation.