The Polarizing Oxford Comma Explained

Defended as a signal of clarity, ridiculed as an unnecessary annoyance, nothing ignites the fire of a grammarian quite like the Oxford comma. If you’ve been lucky enough to have a teacher, colleague, or boss who was particularly passionate about the subject, then you may know that this punctuation easily ruffles feathers (just like the misunderstood semicolon).

So, what is an Oxford comma? The Oxford comma, or serial comma, is used primarily to separate and add clarification to the last item in a list.

The Oxford comma traces its roots to the Oxford University Press, where it was traditionally used by its writers and editors. In the United States, many follow the Associated Press style which never formally adopted its use, making the Oxford comma optional in American English.

This seemingly minor grammatical tool can play a major role in communication. Many awkward conversations have been saved due to the transparency of the Oxford comma. For example, texting your friend about your color options when shopping for a car:

“The dealership has the Jeep Wrangler available in green, silver, yellow and blue.”

Does that mean that the car can be purchased in yellow and also in blue? Or is it available in an elegant, combined yellow and blue option?

Here’s how the sentence would look by inserting an Oxford comma:

 “The dealership has the Jeep Wrangler available in green, silver, yellow, and blue.”

By placing the comma after yellow, it clarifies that these are all separate options and that you’re choosing between four colors.

The practice of omitting the Oxford comma was most likely an effort by many publications to save space. While in many instances using the Oxford comma is a personal preference, there are times such as the above where it’s necessary to avoid ambiguity. 

For another example, we can turn to a court ruling last year. A class-action lawsuit about overtime pay for Maine dairy truck drivers hinged entirely on the use of the punctuation mark. According to Maine state law, workers are not entitled to overtime pay for the following activities: “The canning, processing, preserving, freezing, drying, marketing, storing, packing for shipment or distribution of: (1) Agricultural produce; (2) Meat and fish products; and (3) Perishable foods.”

Note the end of the opening line, where there is no comma before the “or”. Without a comma, the “packing for shipment or distribution” is a single activity. Truck drivers do not pack food, either for shipment or for distribution – therefore they argued these exemptions shouldn’t apply to them.

In fact, the appellate court ruled in favor of the drivers saying that the missing comma created enough uncertainty to side with the drivers. The missing punctuation mark cost the dairy company an estimated $10 million.

The debate will continue to rage on over whether Oxford commas are necessary all the time; in the interim, this ruling upholds the practice of using them when they’re essential to prevent ambiguity.

What do you think? Are you pro-Oxford comma as the standard, or only in specific situations?