The Oxford Comma

The Oxford comma, which is sometimes referred to as a serial comma, is the final comma in a sentence containing list of things, usually coming before and or or. It is used for clarity in a sentence, and its use is often a matter of style, sometimes causing disagreement in publishing and literary circles. Look at the examples below:

I like Jim, John, Jean, Leo, and Mary, all my cousins from New York.

We refuse to the sign a treaty with Russia, Canada, Mexico, or Australia.

The comma coming after Leo and Mexico are the Oxford commas. What purpose do they serve here? In these cases, the Oxford comma’s inclusion is simply a matter of style. The following versions are also correct:

I like Jim, John, Jean, Leo and Mary.

We refuse to the sign a treaty with Russia, Canada, Mexico or Australia.

There is no difference to the meaning of the examples above, but some publications stress you should use the Oxford comma, whereas others ask you to omit it. For example, the United States Government Printing Office says you should use the Oxford comma, whereas The Economist Style Guide opposes typical use. Meanwhile, the Guardian Style Guide cites the Oxford comma as unnecessary, but accepts that its use is at the writer’s discretion.

So, while it might be a question of style, the Oxford comma does have some important uses. Consider the next example which does not use an Oxford comma.

Emma got angry at her parents, David and Anna.

This sentence might suggest to the reader that Emma became angry with her parents, who are called David and Anna. But what if we are trying to convey that Emma got angry with her parents, as well as two other people who are called David and Anna? That is where the Oxford comma comes in to help stop confusion.

Emma got angry at her parents, David, and Anna.

Stylists who do not like the Oxford comma may ask the sentence to be written in a different way to cause less confusion:

Emma got angry at David, Anna and her parents.