There is no global consensus among writers or editors on the use of the serial comma. Most authorities on American English recommend its use, but it is not so frequently used in British English (see extended treatment below, including a survey of published recommendations in Usage and subsequent sections). In many languages (e.g. French, Italian, Polish, Spanish) the serial comma is not normally used, although it may be employed in cases where it aids clarity or the prosody to be used when reading.
Arguments typically advanced for use of the serial comma by default include:
Arguments typically advanced for avoidance of the serial comma by default include:
Many sources, however, are against both automatic use and automatic avoidance of the serial comma, making recommendations in a more nuanced way (see Usage and subsequent sections).
With a comma after cream cheese, the kinds of sandwich are these:
Some writers who normally avoid the serial comma may use one in these circumstances, though sometimes re-ordering the elements of such a list can help as well.
Or consider "They went to Oregon with Betty, a maid, and a cook." The presence of the last comma in the list creates the possibility that Betty is a maid, reasonably allowing it to be read either as a list of two people or as a list of three people, context aside. On the other hand, removing the comma leaves the possibility that Betty is both a maid and a cook; so in this case neither the use nor the avoidance of the serial comma resolves the ambiguity.
A writer who intends that Betty, the maid, and the cook be taken as three distinct people may create an ambiguous sentence, regardless of whether the serial comma is adopted. Furthermore, if the reader is unaware of which convention is being used, both versions are always ambiguous.
These forms (among others) would remove the ambiguity:
The differences of opinion on the use of the serial comma are well characterized by Lynne Truss in her popularized style guide Eats, Shoots & Leaves: "There are people who embrace the Oxford comma, and people who don't, and I'll just say this, never get between these people when drink has been taken.
In Australia, Canada, South Africa and the United Kingdom, the serial comma tends not to be used in non-academic publications unless its absence produces ambiguity. Many academic publishers (for example, Cambridge University Press) also avoid it, though some academic publishing houses in these countries do use it. The Australian Government Publishing Service's Style Manual for Authors, Editors and Printers (6th edition, 2002) recommends against it, except "to ensure clarity" (p. 102).
After each member within a series of three or more words, phrases, letters, or figures used with and, or, or nor.
What, then, are the arguments for omitting the last comma? Only one is cogent – the saving of space. In the narrow width of a newspaper column this saving counts for more than elsewhere, which is why the omission is so nearly universal in journalism. But here or anywhere one must question whether the advantage outweighs the confusion caused by the omission ...
The recommendation here is that [writers] use the comma between all members of a series, including the last two, on the common-sense ground that to do so will preclude ambiguities and annoyances at a negligible cost.Chicago Manual of Style, 15th edition (University of Chicago Press, 2003), paragraph 6.19:
When a conjunction joins the last two elements in a series, a comma ... should appear before the conjunction. Chicago strongly recommends this widely practiced usage....
Texas Law Review Manual on Usage, Style & Editing (10th ed. 2005), R. 1.16The American Medical Association Manual of Style, 9th edition (1998) Chapter 6.2.1:
Use a comma before the conjunction that precedes the last term in a series.
Use a comma between elements (including before and and or) in a series of three or more items.
In a series of three or more terms with a single conjunction, use a comma after each term except the last.The Oxford Style Manual, 2002, Chapter 5, section 5.3 Comma:
"For a century it has been part of OUP style to retain or impose this last serial (or series) comma consistently, [...] but it is commonly used by many other publishers both here and abroad, and forms a routine part of style in US and Canadian English. [...] Given that the final comma is sometimes necessary to prevent ambiguity, it is logical to impose it uniformly, so as to obviate the need to pause and gauge each enumeration on the likelihood of its being misunderstood – especially since that likelihood is often more obvious to the reader than the writer." (pp. 121–122)The CSE Manual for Authors, Editors, and Publishers (Council of Science Editors, 7th edition, 2006), Section 220.127.116.11
To separate the elements (words, phrases, clauses) of a simple series of more than 2 elements, including a comma before the closing “and” or “or” (the so-called serial comma). Routine use of the serial comma helps to prevent ambiguity.Garner's American Usage (Oxford, 2003)
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.
Most college writing handbooks in the U.S. also advocate use of the serial comma.
Avoid the so-called Oxford comma; say "he ate bread, butter and jam" rather than "he ate bread, butter, and jam".The New York Times stylebook:
In general, do not use a comma before and or or in a series: The snow stalled cars, buses and trains.The Economist style manual:
Do not put a comma before and at the end of a sequence of items unless one of the items includes another and. Thus 'The doctor suggested an aspirin, half a grapefruit and a cup of broth. But he ordered scrambled eggs, whisky and soda, and a selection from the trolley.'The AP Stylebook:
Use commas to separate elements in a series, but do not put a comma before the conjunction in a simple series: The flag is red, white and blue. He would nominate Tom, Dick or Harry.
Put a comma before the concluding conjunction in a series, however, if an integral element of the series requires a conjunction: I had orange juice, toast, and ham and eggs for breakfast.
Use a comma also before the concluding conjunction in a complex series of phrases: The main points to consider are whether the athletes are skillful enough to compete, whether they have the stamina to endure the training, and whether they have the proper mental attitude.The Australian Government Publishing Service's Style Manual for Authors, Editors and Printers:
A comma is used before and, or, or etc. in a list when its omission might either give rise to ambiguity or cause the last word or phrase to be construed with a preposition in the preceding phrase: "There were many expeditions, including those of Sturt, Mitchell, Burke and Wills, and Darling." "The long days at work, the nights of intense study, and inadequate food eventually caused them serious health problems." "The sea, the perfume of wisteria, or a summer lunch: any of these revived memories of an easier time." "We needed to know how to get there, what time to get there, the number of participants, etc."
Generally, however, a comma is not used before and, or or etc. in a list: "John, Warren and Peter came to dinner." "Fruit, vegetables or cereals may be substituted." "Why not hire your skis, boots, overpants etc.?"The Guardian Style Guide:
a comma before the final "and" in lists: straightforward ones (he ate ham, eggs and chips) do not need one, but sometimes it can help the reader (he ate cereal, kippers, bacon, eggs, toast and marmalade, and tea)University of Oxford Writing and Style Guide:
As a general rule, do not use the serial/Oxford comma: so write ‘a, b and c’ not ‘a, b, and c’. But when a comma would assist in the meaning of the sentence or helps to resolve ambiguity, it can be used – especially where one of the items in the list is already joined by ‘and’:
They had a choice between croissants, bacon and eggs, and muesli.