November 5 2009

Using “that” and “which”

by Barbie in Grammar

An executive at a company I worked for several years ago was surprised when I changed “which” to “that” and “that” to “which” in many instances in a company proposal that I edited. He explained that someone once told him that he used “that” too often, so he started alternating the use of “that” and “which” for variety.

Unfortunately, the interchangeability of “that” and “which” is a common misperception. It is rare that I edit a document that doesn’t have at least a few “that/which” errors.

Luckily, the guidelines for using “that” and “which” are simple. Here is how you determine whether you should use “that” or “which:”

That is used with restrictive clauses. A restrictive clause limits the subject in some way. That is not preceded by a comma.

Example: The group that wins the award receives a $100 gift certificate.

The restrictive clause “that wins the award” qualifies or limits the subject (the group). By using a restrictive clause, we understand that only the group that wins will receive the prize. Removing this clause would change the meaning of the sentence.

Which is used with nonrestrictive clauses. A nonrestrictive clause provides additional information that does not limit the subject. Nonrestrictive clauses are enclosed in commas.

Example: Carpenter Document Consulting, which increased its client base last quarter, is now hiring.

This nonrestrictive clause provides additional information about the company, but it does not limit the subject (Carpenter Document Consulting) in any way. It can be removed without impacting the meaning of the sentence.