Do I Need to Use the Oxford Comma?

If you’ve been on social media at all and paid attention to grammar arguments, you may have seen a lot of discussion about the Oxford comma and whether writers need to use it.

The Oxford comma—or serial comma—is the comma that appears before the final item in a series, such as:

  • The colors of the American flag are red, white, and blue.
  • The most popular pizza toppings are pepperoni, mushrooms, and olives.

Some people insist that this final comma is unnecessary and that those sentences are just as intelligible if written:

  • The colors of the American flag are red, white and blue.
  • The most popular pizza toppings are pepperoni, mushrooms and olives.

Arguments For and Against

At this point, the pro-comma faction will argue that the Oxford comma helps to resolve ambiguity: what if the final two items are really one item like franks and beans? The comma, they argue, helps to mark such a phrase as one item rather than two.

To that objection the anti-comma faction responds that there is no instance in which a compound like franks and beans would be misinterpreted. They point out that there will always be an additional and to clear things up:

  • My favorite summertime foods are hamburgers, corn on the cob and franks and beans.

The anti-commaists point out that the first and lets the listener know that whatever is said next is the final item in the list, even if it’s a compound phrase like franks and beans. This argument is a strong one. It is difficult to think of an instance where the use of the first and would not resolve the ambiguity.

The Real Ambiguity

The problem is, that you can’t always tell whether you’re dealing with a series in the first place. That is, not all nouns or items listed together are in a series. Somtimes, words in a list are modifying each other. It’s not always clear which is which.

For example, how many people are we talking about in the following sentence?

  • I went to the movies with my cousins, Teniqua and Damon.

Is the speaker speaking of at least four people—Teniqua, Damon, and a number of unnamed cousins—or two people: Teniqua and Damon, the speaker’s cousins?

This is where the Oxford comma becomes really helpful, and where its alternate name “serial comma” becomes most relevant. If nothing else, the serial comma lets us know that we’re dealing with a series of items, rather than some items used in an appositional or descriptive way, modifying something else in the sentence.

  • I went to the movies with my cousins, Teniqua, and Damon. (series)
  • I went to the movies with my cousins, Teniqua and Damon. (appositional use)

So, it’s not that the serial or Oxford comma is needed to resolve ambiguity within a series; it’s necessary to resolve the ambiguity over whether listed items are a series or not.

As always, the main rule for writing and usage is clarity and comprehensibility. You can use your judgment and make your own choices as long as the meaning you’re trying to convey is not lost. But defaulting to the Oxford comma can increase the chances that your writing is clear and communicates what you want it to.