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How much does a comma cost? Probably more than you expect.

In early February 2018, the serial comma — that little comma before a conjunction (and, so, but, etc.) within a list — cost Oakhurst Dairy $5 million. The drivers sued their Portland, Maine–based employer for unpaid overtime hours. They built their case around a missing serial comma in their contract’s exemption clause:

The canning, processing, preserving, freezing, drying, marketing, sorting, packing for shipment or distribution of:

  • Agricultural produce;
  • Meat and fish products; and
  • Perishable foods.

So, where’s the problem? Confusion lies in the relationship between the words “packing,” “shipment,” and “distribution.”

The drivers’ attorneys argued that without a serial comma after the word “shipment, ” “packing” refers to “shipment” and “distribution.” Ultimately, the court agreed that omitting the serial comma gave the clause “packing for shipment or distribution of” two meanings. The ambiguity hurt Oakhurst Dairy’s contractual intentions and resulted in serious confusion.

How does the serial comma work?

Though the serial comma may seem trivial, the grammatical mark clearly defines the relationship between items in a list. By placing a comma before the conjunction and last item, the writer leaves no chance for confusion.

Consider a simple example. The following sentence first appeared in a review of a movie about the country music legend Merle Haggard:

Among those interviewed were his two ex-wives, Kris Kristofferson and Robert Duvall.

Because the conjunction “and” connects the last two items in the list, we could mistake country outlaw Kris Kristofferson and Oscar-winner Robert Duvall as Haggard’s ex-wives. Though that love triangle would have surely produced some amazing songs, sadly, the three men never married each other.

Why does it matter?

While our example above may seem simple, confusion compounds once you create more complex sentence structure and have additional context to weigh in.

When we cannot connect the relationships between words, we’re forced to assume meaning (or just stop reading altogether) — and leaving details to assumptions rarely is foolproof. Serial comma skeptics may argue that extra commas can clutter writing and underestimate the reader’s intelligence, but we believe in clarity. When you leave no room for confusion, you better protect yourself and your company, which Oakhurst Dairy learned the hard way.

When in doubt, aim for what provides clarity for your reader. And the next time you take your commas for granted, remember the cost of confusion.