Serial Commas and Their Virtues

Those of you who already know me, know that I glow when I talk about commas.

My favorite comma of all is the serial comma, also known as the series comma, Oxford comma, and Harvard comma.

A serial comma is the comma that is used after the penultimate item in a list of three or more items before the conjunction “and” or “or.” For example, consider this sentence: “I am applying to Columbia, Cornell, and MIT.” The comma after “Cornell” and before “and” is the serial comma.

Why do I extol serial commas? Because serial commas clarify. They shed light on meaning. They vanquish ambiguity.

Serial commas eliminate the possibility of misinterpretation. For example, take this example from the MLA Style Center: “Lia ordered three smoothies: strawberry, peach and mango and pineapple.” Without a comma after peach or mango, we don’t know if “peach mango” is the flavor of one smoothie ordered by Lia or if “mango pineapple” is.  Or consider this more famous example: “This book is dedicated to my parents, Ayn Rand and God.” Yes, that sentence was published and yes, that writer did regret it.

Serial commas can even make you wealthy.

During the late 19th century, the serial comma earned a second name, the “Oxford comma.” This after the Oxford University Press style guide of the time mandated its use. Calling the serial comma the Oxford comma lends that little squiggle of punctuation an aura of class and even prestige not shared by other punctuation marks.

Oxford comma dispute settled; Maine drivers awarded $5 million

In 2014, drivers for the Oakhurst Dairy company of Portland, Maine filed a lawsuit claiming that they had not received the overtime pay for which they were eligible. According the Maine law, workers are entitled to time-and-a-half pay for each hour worked after 40 hours. But the law exempts those who perform the following duties:

“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.”

The trouble with this sentence lies with the ‘or.’ Without a comma after “shipment,” the sentence is confusing: Is “packing for shipment or distribution” a single overtime-exempt activity, or are “packing for shipment” and “distribution” two distinct activities that are both exempt?

According the drivers, the sentence means that those who engage in either “packing for shipment” or those engaged in “distribution” are exempt. As the sentence is written, they argued, distribution wasn’t in a category of activity of its own, and because the drivers don’t engage in packing for either purpose, the law doesn’t apply to them. In addition, they continued, if “distribution” was intended to be a separate exempt activity, why didn’t the law use the gerund form of the verb (distributing) as was used to describe all the other activities listed?

(You can see how grammarians can really get into this lawsuit.)


The judges concluded that the lack of the comma made the legal language ambiguous, and that the ambiguity “must be construed liberally.” In the end, they took the side of the drivers. The settlement awards the five drivers who brought the lawsuit $50,000 each. The other drivers, about 127 in all, are also covered by the settlement and will be paid the overtime pay they are due.

This is not the first time that ambiguous punctuation has caused legal problems. 

So let’s give thanks Aldus Manutius, the 15th-century Italian printer who, bent on banishing confusion and ensuring intelligibility, invented the comma. (In the Greek, komma means “something cut off,” or a “segment.”) 

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Dr. Osborn works with students from all over the world to help them reach their independent, college, and graduate school goals. Through a personal, one-on-one approach, Dr. Osborn creates an individualized plan for each student based on the student’s strengths, passions, and career aspirations. Her holistic approach helps students perform well in school and secure admission to top colleges.  

About The Author

Susan Osborn, Ph.D., has spent 30 years in higher education, in admissions at Vassar College, in the English department and Writing Program at Rutgers University, in the lab at The New Jersey Center for Research on Writing, and as a private tutor. Dr. Osborn is also an award-winning writer and scholar and she brings both her education smarts and her writing smarts to every student relationship.