Professional Style

Restrictive vs. Nonrestrictive

July 2008
Spot the Error

Can you tell the difference between these two sentences?

  • My boss’s wife, Helen, is the county sheriff.
  • My boss’s wife Helen is the country sheriff.

The first sentence tells us that the boss’s wife, whose name happens to be Helen, is the county sheriff.  The second sentence tells us that the boss is a polygamist. 


Yeah.  Leave out two little commas and look what happens.

That’s the difference between a restrictive phrase and a nonrestrictive phase.  (Oops.  Sorry.  I should have warned you that I was going to use grammar terms.  Breathe.  You can get through this.)

By omitting the commas, the second sentence says, in essence, that the boss has more than one wife, and Helen is the one who is sheriff.

Let’s take a closer look.

Most of us are familiar with the nonrestrictive phrase (the one with the commas). We know that when we use the two commas around a phrase (or a name), that we’re providing supplemental information that could be omitted without confusing the reader.

There are times, however, when the no-comma format (or restrictive phrase) is required.  Let’s say Sharon has three sons, Brad, Brian, and Brett.  And one of her sons was accepted to Harvard.  We would write:

Sharon’s son Brad graduated from high school in the top one percent of his class, and he plans to attend Harvard Business School in the fall.

We eliminate the commas because the name “Brad” is required.  It defines which of Sharon’s sons we’re talking about.

Confused? Let’s look at this a different way. If we include the commas in the sentence above (as we would for a nonrestrictive phrase), it would mean that “Brad” is just supplemental information, and the name could be removed. But, if we remove “Brad,” readers would be confused; they wouldn’t know which of Sharon’s sons is going to Harvard. Therefore, since “Brad” is NOT just supplemental information (it’s required information), the name is NOT set off by commas.

Here are a couple of additional examples:

My colleague Daniel came up with the idea to target the senior market for the health club’s advertising campaign.  (Out of all my colleagues, Daniel was the one who had the bright idea.)

Cathi’s friend, Lisa, moved to Canada a year ago. (Cathi’s only friend in the world, whose name happens to be Lisa, moved away, and now Cathi is one lonely girl.)


  • Nonrestrictive phrase – supplemental information – uses commas.
  • Restrictive phrase – required information – no commas.

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