July 8, 1997

serial comma

When writing a "list" sentence in which several different points are listed, and the last item in the sentence is preceded by the word "and," should a comma be used in front of the word "and" or is it not necessary? It is a minor point, but as I have minutes to begin next week, I am most curious of the proper grammatical structure.

A comma after the next-to-last item in a list, when the next-to-last item and the last item are separated by a conjunction, is known as a series comma or a serial comma (or, in England, as the Oxford comma). An example is: "We visited London, Paris, and Milan." Without the serial comma the sentence would be "We visited London, Paris and Milan." Sometimes the omission of the comma can make a sentence ambiguous: "He ordered coffee, bread and butter and a muffin." This could mean that "bread and butter" is one item ordered together, or that "butter and a muffin" were ordered together; one can't tell from context. The debate about whether or not to use it is a stylistic issue, not a grammatical one, but it's a noisy debate nonetheless.

Some people, chiefly journalists, think that the serial comma should be avoided unless the sentence is ambiguous, on the grounds that the conjunction makes the preceding comma superfluous. Most, however, recommend using the serial comma in all cases, since the inclusion of the comma is always clear and doesn't force the writer to evaluate every sentence for possible ambiguity.

Most newspaper style books--for example, those of the A.P. and the New York Times--recommend omitting the serial comma, and many newspapers and newsmagazines don't use it. Most book publishers do use the serial comma, and most non-newspaper-related style guides recommend using it.

I myself strongly recommend using the serial comma, and find its absence distracting.

I should also point out that if a sentence is complex, and has lists which themselves contain commas or clauses, a semicolon should be used instead of a comma: "He ran out of the office; went to the gym, doing only half of his normal workout; took a cab home to pick up the dogs; and made it to the train station with two minutes to spare."