The Serial Comma Can Cause Ambiguity

The serial comma is the comma used immediately before the and or or preceding the final item in a list of three or more items. I wrote about the serial comma in this 2010 post, but I revisit it now because something caught my eye in Garner’s Modern American Usage.

Here’s what it says on page 676:

Whether to include the serial comma has sparked many arguments. But it’s easily answered in favor of inclusion because omitting the final comma may cause ambiguities, whereas including it never will ….

I think that’s incorrect, in that in addition to allowing you to avoid ambiguity, the serial comma can in certain circumstances cause ambiguity. Here’s what MSCD 12.61 says:

But the serial comma can also create ambiguity. Consider the following adjusted version of the dedication [discussed in the preceding paragraph]: To my mother, Ayn Rand [,] and God. With the serial comma, the reader could understand the dedication as meaning either that the book is dedicated three ways or that the book is dedicated to the writer’s mother, who happens to be Ayn Rand, and to God. Omitting the serial comma makes the latter meaning less likely.

Of course, whenever presence or absence of a comma can change meaning, it would be prudent to restructure the sentence to avoid that nuance.
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About the author

Ken Adams is the leading authority on how to say clearly whatever you want to say in a contract. He’s author of A Manual of Style for Contract Drafting, and he offers online and in-person training around the world. He’s also chief content officer of LegalSifter, Inc., a company that combines artificial intelligence and expertise to assist with review of contracts.

7 thoughts on “The Serial Comma Can Cause Ambiguity”

  1. But omitting the serial comma from your example — as in, “To my mother, Ayn Rand and God” — raises an interesting possibility, namely that the dedicator’s mother is simultaneously Ayn Rand and God. That would be especially remarkable given Ms. Rand’s reputation for virulently-atheistic views (which may have been part of the point of the example in the first place).

    Your last paragraph points in the right direction. If in fact the dedicator wants to imply that the putatively-childless Ms. Rand secretly gave birth to (or adopted) him (or her), then the serial comma is appropriate, along with another “to,” so that it reads thusly: “To my mother, Ayn Rand, and to God.” Or perhaps: “To my mother — Ayn Rand — and God.”

    On the other hand, if the author intended a trisected dedication, then a semi-colon might be in order; that seems to be a best practice when dealing with lists: “To my mother; Ayn Rand; and God.” To get even funkier, the author could add a colon: “To: my mother; Ayn Rand; and God.”

    • I’m afraid a semicolon may not be used in that position. Furthermore, the author’s use of the Any Rand example proves the opposite of his interpretation, i.e., that the serial comma is essential. The appositive created by the lack of the serial comma creates the ambiguity. Finally, please refrain from using “either” with three or more examples; similarly, “both” may not be used.

      You legal beagles would enjoy reading about the Maine overtime statute in which workers have been granted $10,000,000 because the statute did not include a serial comma. I’ll stick to English stuff.

  2. Congratulations for seeing what so many people seemingly can’t.

    It’s not rocket science. It simply boils down to whether the second (or the second and third) elements in a three-part list can be mistaken for an appositive of the first.

    In general terms:

    1) X, Y and Z (without serial comma) can be confusing if “Y and Z” can be mistaken for an appositive of “X”.

    2) X, Y, and Z (with serial comma) can be confusing if “Y” can be mistaken for an appositive of “X”.

    For example:

    1) my parents, Elvis and Marilyn (are they really your parents? Wow)

    2) my father, Elvis, and Marilyn (son of the King … or perhaps not)

    “The serial comma is never wrong” is wrong. It can be confusing or ambiguous – which in the law can be pretty disastrous.

  3. Rephrase it “To my mother, who to me has been both Ayn Rand and God,” and I am definitely buying that book. This post brought to you by Quality Nonsense, the square circle people, and nice, too.

  4. So far, every example I have seen of ambiguity caused by a serial comma involves a noun or noun phrase being mistaken for an appositive. Does anyone have a different example? Relatively few sentences present that particular opportunity for misreading, whereas many series are likely to be misread, at least momentarily, without the serial comma. Using the serial comma consistently is best if your intent is to be clear. In the rare cases where a word or phrase in a series could be misunderstood as an appositive, the solutions are simple.


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