Booher's Rules of Business Grammar - Dianna Booher 2009

Which hunts
Pesky pronouns: The understudies

THAT VERSUS WHICH

Which of the following two sentences is correct?

People do not buy products which seem overpriced and shabbily packaged.

People do not buy products that seem overpriced and shabbily packaged.

You can verify the correct answer for yourself in just a moment. The distinction between these two is not difficult if you keep this one simple test in mind: Does the key point of the sentence change if you remove the that or which clause? (A clause is a group of related words with a subject and verb.)

If you can remove the clause in question and not change the meaning of the sentence, use a comma and which to set it off from the rest of the sentence. If you can’t, use that without a comma. Simple enough, right?

Circle back to the top of the page and identify the correct sentence. Remove “which seem overpriced and shabbily packaged,” and you’re left with “People do not buy products.” This remaining part definitely makes no sense. The that clause is essential to its meaning. So the second sentence is the correct one of the two.

Other Examples:

Ebeneezer submitted his sales report, which was late as usual. (Just added information—you can omit the which clause and not lose the gist of the sentence.)

Mortimer parked his car in front of the building that faces Montgomery Street. (You can’t omit the that clause, or you’ll lose the gist of the sentence. He’s telling you which building he parked in front of—the building that faces Montgomery Street.)

Just to cement this in your mind, let’s say there’s only one building in the entire area. Suppose the writer is telling you that Mortimer parked in front of the building, not behind it. Here’s how the sentence would be written: “Mortimer parked his car in front of the building, which faces Montgomery Street.” Now the which clause is simply nonessential information that doesn’t distinguish this building from any other.

Memory tip

Think of which clauses as “switch” clauses. The which signals the reader that you’re switching off track briefly to provide additional, nonessential information. Use a comma to set off this side note.