Last week, the United States Court of Appeals for the First Circuit decided a case that addressed the Oxford comma and how omitting it from a sentence can create ambiguity.
For those who are unfamiliar with the “Oxford” or “serial” comma, it refers to the punctuation convention of inserting a comma before the conjunction in a series of three or more items—A, B, and C. Most U.S. newspapers omit the last comma in a series—A, B and C. The Associated Press style guide canonizes this omit-the-last-comma convention. But the AP’s rule isn’t as simple as just omitting the comma before an and or an or.
Instead, the AP hedges: It tells writers to omit the last comma unless omitting it would create confusion or ambiguity.
There are several problems with the AP’s rule.
First, the AP rule requires the writer to scrutinize every list of three or more items to determine whether omitting the last comma before the conjunction may be confusing or ambiguous to readers. If writers follow the AP’s subjective rule, they will invariably spend more time writing, editing, and proofreading their work. The vastly easier—and less risky approach—is to always insert the comma before the conjunction. A Murphy’s Law of Ambiguity applies to these situations: Writers will seldom recognize when a sentence is ambiguous because they subjectively know what the sentence means. Why go through all the work when the fix is so easy?
Second, writers who follow the AP rule may also appear to readers to be inconsistent, at best, and sloppy, at worst, with their punctuation. In some sentences that contain a list of three or more items, writers may insert the comma because the sentence would be ambiguous without it; in other sentences, they won’t because they subjectively believe that there’s no ambiguity. This haphazard punctuation style may give close readers the justified impression that the writer is careless with punctuation.
Furthermore, the inconsistency that comes with following the AP style can give opposing counsel good reason to argue—and for courts to find—that the writer intended different meanings by omitting the comma in one list of items, but not in another list—in other words, that the drafter was doing or intending something other than simply following the AP’s subjective rule.
Finally, the AP rule doesn’t have much regard for readers. If the writer omits the last comma, both sophisticated and ordinary readers must often read a sentence two or three times to determine where the next-to-the-last item ends and the last item begins, especially when the items are long or complex. If fact, I’ve never read an edition of a newspaper that follows the AP rule without having to reread at least one sentence to understand what the writer intended. The Oxford comma always makes for easier reading; it never confuses.
It’s true that advocates of the AP rule have cherry-picked examples where inserting the Oxford comma changed the intended meaning of a sentence. But they ignore that the AP rule creates more unclear sentences and that simply including the Oxford comma in these sentences is an easy fix.
These advocates also ignore the cardinal rule of clear written communication: Punctuation should not be used as first aid for ailing sentences. In those cases where an Oxford comma arguably changes the meaning of the sentence, it’s the writer’s job to rewrite the sentence to make the meaning clear. If a sentence that includes the Oxford comma winds up being unclear or ambiguous, it’s the writer’s fault, not the comma’s.
John Hightower is the law librarian for the Lanier Ford law firm in Huntsville, Alabama, and has taught writing to professionals for more than 40 years. He received his J.D. from the University of Mississippi in 1975.