Perhaps no mark of punctuation ruffles feathers more than the serial comma (also called series comma, Oxford comma, and Harvard comma). This comma precedes the final item in a list or series, before the word and or or. With the exception of newspapers, most publications use the serial comma, because it helps writers avoid ambiguity. Who would object to unambiguous prose? you might ask. Fair-weather comma users: publications that do not require the serial comma may use it only when misreading results. Proponents of the serial comma, like the MLA, would decry the inconsistency of the use-it-when-you-need-it approach and advocate using the serial comma in all series of three or more items or phrases.
Here’s an example where omitting the serial comma results in ambiguity:
Lia ordered three smoothies: strawberry, peach and mango and pineapple.
Without a serial comma placed after peach or after mango, it isn’t clear if “peach and mango” is one flavor or if “mango and pineapple” is.
Here’s another example:
Sam took his dog for a walk and ran into Deirdre, a friend and his dentist.
As written, the sentence might mean that Deirdre is a friend of Sam’s and also his dentist. But, alternatively, the sentence might mean that Sam met three people, not one: Deirdre, a friend, and his dentist. Without the serial comma, there’s no way to know.
When items in series themselves contain commas, additional punctuation is needed to clarify the items. Consider this sentence:
The invited speakers are the association’s president, the vice president, the councilwoman, Suzette Tanner, and Walter McCarthy, the executive director.
Here, commas aren’t enough to clarify the items in the series: is the councilwoman named Suzette Tanner or are Suzette Tanner and the councilwoman two people? Adding serial semicolons provides clarity:
The invited speakers are the association’s president; the vice president; the councilwoman, Suzette Tanner; and Walter McCarthy, the executive director.
The semicolons make it clear that there are four speakers. To use serial semicolons, place them wherever you would normally place serial commas, to separate like terms. Here’s a more complex example where serial semicolons are needed:
In his report, Mr. McCarthy presented on the annual budget, the plans to hire a director of operations, a chief financial officer, and a human resources assistant, the fund-raising efforts of the development committee, which expects to meet its goal by the end of the fiscal year, the recent accomplishments of the committees on accessibility, research, and sustainability, and the restructuring of the product development team.
The addition of serial semicolons makes clear which items belong together and makes the sentence easier to read:
In his report, Mr. McCarthy presented on the annual budget; the plans to hire a director of operations, a chief financial officer, and a human resources assistant; the fund-raising efforts of the development committee, which expects to meet its goal by the end of the fiscal year; the recent accomplishments of the committees on accessibility, research, and sustainability; and the restructuring of the product development team.
Still not convinced of the importance of the serial comma? A court ruling in a labor dispute earlier this year upped the stakes of this normally low-profile punctuation mark. The decision centered on the absence of a serial comma in a Maine state law, which could end up costing a company millions of dollars in overtime pay to truck drivers. An appeals court agreed with the drivers that the missing comma rendered the interpretation of the law ambiguous, and the lawyer representing the drivers credited the absence of the comma with winning them the case (Victor). A win for the drivers and for champions of the serial comma!
Victor, Daniel. “Lack of Oxford Comma Could Cost Maine Company Millions in Overtime Dispute.” The New York Times, 16 Mar. 2017, www.nytimes.com/2017/03/16/us/oxford-comma-lawsuit.html.
Bob Grove 31 October 2017 AT 07:10 AM
Good morning. In your final example of the use of semicolons, wouldn't the first phrase be betters served by a colon as shown below?
In his report, Mr. McCarthy presented on the annual budget: the plans (etc.).
Erika Suffern 02 November 2017 AT 09:11 AM
Bob, thanks for your question. In the example, "the annual budget" is the first item in the series. Using a colon after that item would make the items that follow subordinate to "the annual budget" (parts or aspects of the annual budget), which is not the intention.
Fred 20 February 2018 AT 03:02 PM
“Lia ordered three smoothies: strawberry, peach and mango and pineapple.”
This is obviously three drinks because it would be terrible style to substitute an “and” for a comma. Four drinks would be “strawberry, peach, mango and pineapple.” Therefore, the comma is unnecessary.
“Sam took his dog for a walk and ran into Deirdre, a friend and his dentist.”
If you put a comma after “friend,” it could read that he ran into two people. “Deirdre, a friend, and his dentist.” “Friend” now becomes a description of Deirdre. The solution here is to write the sentence unambiguously.
As for Bob Grove’s (incidentally, I once had an incredibly talented English teacher by that name) example, the colon should go after “on.”
I have never been able to discover a single example of a sentence which requires the Oxford comma. Those presented either require correct punctuation (usually a colon) or rewriting.
Fred 20 February 2018 AT 06:02 PM
As an alternative in the first example, put "mango and pineapple" first. Thus, "three smoothies: mango and pineapple, strawberry and peach." with no need for the Oxford comma.
Lily Thompson 25 September 2018 AT 03:09 PM
I think you're missing the point Fred. In the smoothie example, the drinks could be: strawberry, peach and mango, and pineapple; OR they could be: strawberry, peach, and mango and pineapple. Thus, you do need the serial comma to know which fruit is combined with which.
Eli 23 June 2022 AT 01:06 PM
Unfortunately, in your example of why the Oxford Comma is unnecessary, I honestly have no idea if the last two drinks are "peach and mango" and "pineapple" or if they are "peach" and "mango and pineapple."
However, with an Oxford Comma, we could easily know how to group them:
“Lia ordered three smoothies: strawberry, peach, and mango and pineapple,” or “Lia ordered three smoothies: strawberry, peach and mango, and pineapple.”
Eric Johnson 13 April 2018 AT 09:04 AM
Thank you! I learned the serial comma as a child but didn’t know it’s proper term. I’ve been using it for 30 years and nearly everyone has told me it’s unnecessary. Vindication!
Jeremiah Malenfant 26 April 2018 AT 11:04 PM
Your example, “three smoothies: mango and pineapple, strawberry and peach.” requires the reader not to expect an Oxford comma in order for them to interpret "mango and pineapple" as one smoothie but "strawberry and peach" as two separate drinks and thus would disrupt a reader's train of thought as they read. Is it really so much easier to entirely reword a list because of some vendetta against a comma you were told was unnecessary once than to press the comma key one more time? Requiring your reader to puzzle out your sentences based on their knowledge of the finer points of proper English punctuation is certainly not going to ingratiate you to them, nor will it encourage them to read further.
Dusti 14 October 2021 AT 03:10 PM
Probably the most correct form of this sentence would be: “Lia ordered three smoothies: strawberry, peach and a mango and pineapple blend.”
If you really were that opposed to adding two extra words, I suppose you could write it this way as well: “Lia ordered three smoothies: strawberry, peach and mango-pineapple.”
There really is no need for serial commas if you know how to write properly.
Yana Gounova 02 August 2018 AT 02:08 PM
In the following sentence, do we need the comma after "careers"? It appears to me that the part before it is not parenthetical, and if using the comma, we'd be separating a subject from its verb. So I would remove it. Thoughts?
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Erika Suffern 07 August 2018 AT 10:08 AM
That is correct. A serial comma belongs before the last item in a series but not after the last item.
Lucretia Head 19 August 2018 AT 03:08 AM
Erika, I was told that the MLA8 revision of serial commas is that the last comma before and is not needed anymore. Is that true?
Erika Suffern 22 August 2018 AT 09:08 AM
The eighth edition of the MLA Handbook, published by the MLA, uses serial commas.
Kim McDonald 18 September 2018 AT 02:09 PM
Wouldn't Fred's suggestion to put a colon after "on" in the example sentence be a non-standard use of a colon? I was taught a colon can only be used after an independent clause. It should not separate a preposition from its objects or a verb from its complements.
Erika Suffern 20 September 2018 AT 09:09 AM
A colon may be used to introduce a list. You may be interested in another post we published, on using colons: https://style.mla.org/colons-how-to-use-them/.
Kathy Jorgensen 01 October 2018 AT 05:10 PM
I read the "colon in a list" section of the link you posted in your response to Kim McDonald's question about using a colon after "on," and it contradicts your response. In all three instances, the link indicates or shows that the clause preceding the comma must be independent. Here it is, cut and pasted:
Introducing a Series or List
Use a colon with the phrases as follows and the following.
To make a cake you need the following ingredients: butter, sugar, eggs, milk, flour, leavener, and salt.
Combine the ingredients as follows: first, cream the butter with the sugar; second, add the eggs and milk; third, add the flour, leavener, and salt.
Use a colon before a series or list only if the words that introduce the list make up a complete sentence:
To make a cake you need a few basic ingredients: butter, sugar, eggs, milk, flour, leavener, and salt.
If the words before the colon do not constitute a sentence, do not use a colon:
To make a cake you need butter, sugar, eggs, milk, flour, leavener, and salt.
Lily Thompson 25 September 2018 AT 03:09 PM
Question: I remember being taught (granted, a long time ago) that when using serial semicolons in a list, one would use a comma for the very last semicolon. Not sure why now or in what context I was taught that. Is this incorrect?
Erika Suffern 26 September 2018 AT 09:09 AM
In a series that requires semicolons, use the semicolons wherever you'd normally put serial commas. There's no reason to treat the last semicolon differently from the others.
Perri 28 September 2018 AT 01:09 PM
I haven't been able to find an answer to this question: How do you end the series of semicolons if the last element isn't the end of the sentence? For example, "He worked in New York City; Helena, Montana; Cincinnati, Ohio; and Kansas City, Missouri, before settling down." Should the punctuation after "Missouri" be a comma or semicolon?
Erika Suffern 28 September 2018 AT 03:09 PM
Peter Kruger 27 December 2018 AT 07:12 PM
Should the Oxford comma be used in titles? Or next to a ampersand? I’m specifically considering it for a resume:
Education, Philanthropy, & Honors
I would like to keep the ampersand for style and spacing on the page but the comma next to it looks odd to me.
Erika Suffern 28 December 2018 AT 09:12 AM
Your instinct is correct. Omit a serial comma when using an ampersand. But, generally speaking, use a serial comma in titles you write.
Michael H Lee 22 January 2019 AT 08:01 PM
Is it appropriate to use a semi-colon instead of a comma to separate two items in a list, where one item includes commas as part of the description? Or does the list have to be more than 2 items to use semi-colons?
Erika Suffern 23 January 2019 AT 09:01 AM
Two items do not constitute a series. In most cases you would connect two items with and or or, not with punctuation.
Michael H Lee 23 January 2019 AT 12:01 PM
For example, "We sell various kinds of wine, including Cabernet, Merlot, Zinfandel and Pinot Noir, and spirits." This would be correct instead of "Pinot Noir; and spirits."
Erika Suffern 28 January 2019 AT 09:01 AM
The semicolon is not correct. Consider recasting your sentence: "We sell spirits and various kinds of wine, including Cabernet, Merlot, Zinfandel, and Pinot Noir.”
Bill R. 23 January 2019 AT 10:01 PM
I'm updating a manual for work and am not sure where to put the semicolon in the following passage under section A. There are more investment functions listed (through E), but I only included the first couple here as an example. Thank you in advance!
The General Manager will carry out all investment functions of the System including, but not limited to:
A. In consultation with the Chief Investment Officer and System consultants, recommending investment policies and strategies to the Board [Section 509(d)];
B. Managing investment staff and external service providers in the implementation of all policies and strategies;
Allison 25 January 2019 AT 12:01 AM
Is there a citation for the serial semicolon from the mla citation guide? My doctoral advisor would like me to change my serial semicolons to commas but then my sentences would be a complete mess. I may be able to convince her to keep the serial semicolons if I could direct her to the correct passage in the mla citation guide.
Erika Suffern 28 January 2019 AT 09:01 AM
Allison, you can find information about serial semicolons on p. 70 (3.2.3b) of the 7th edition (2009) of the MLA Handbook. It is not in the 8th edition. You might also point your adviser to this post (this is the official, authorized Web site of MLA style, written and edited by the same team that publishes the Handbook.)
Brad 06 February 2019 AT 03:02 PM
Nice, clear, and informative article! :)
So here's a question: When there is a list of titles of, say, songs, do the commas or semicolons go inside or outside of the quotes? For example: "I Love You, I Think;" "Oh, that I Could Understand Lists with Commas;" "Let's End This."
Or is this correct?: "I Love You, I Think"; "Oh, that I Could Understand Lists with Commas"; "Let's End This."
sam 07 March 2019 AT 10:03 AM
How would you treat a list of items when only the last item is separated by commas? Can you use commas to separate the others, or do you need semicolons?
The subject raises questions about fiduciary duties; disclosure obligations; escalation procedures; investor remuneration; and the appropriate roles for the first, second, and third lines of defense.
The subject raises questions about fiduciary duties, disclosure obligations, escalation procedures, investor remuneration, and the appropriate roles for the first, second, and (if applicable) third lines of defense.
Erika Suffern 07 March 2019 AT 11:03 AM
Great question! When only the last item in a series contains commas, you do not need to use serial semicolons, as long as no ambiguity results.
Bilal H. E. 29 March 2019 AT 01:03 AM
Yet there are times when the Oxford comma could create ambiguity. "I went on a walk with Jenny, my sister, and her friend." If we adopt the Oxford comma system, there are two meanings to this sentence. Jenny could be my sister, or this could be a list of three with an Oxford comma. Whereas if we reject the Oxford comma system, we know that "I went on a walk with Jenny, my sister, and her friend" is not a coordinated list of three. Jenny is just the name of my sister. The list of three could only be "I went on a walk with Jenny, my sister and her friend." Here the Oxford comma system reduces clarity and makes the sentence ambiguous. Cases like this may be rare, but they seem just as rare as cases where having no Oxford comma creates ambiguity.
Erika Suffern 01 April 2019 AT 10:04 AM
Thanks for your comment. A writer or publishing style should use or omit the serial comma consistently, which aids in clarity. In cases where using a serial comma may introduce ambiguity, we prefer to recast the sentence.
Kimberly Gorman 11 May 2020 AT 03:05 PM
For items with serial commas within parentheses, would you separate each item by commas or semicolons? For example:
Timmy has cars (red, green, and blue), bouncy balls (white, gray, and pink), and blocks (purple, brown, and black).
Timmy has cars (red, green, and blue); bouncy balls (white, gray, and pink); and blocks (purple, brown, and black).
Chris Montemayor 28 November 2021 AT 04:11 PM
It's the first. (Parentheses ROCK.)
Casey 26 May 2020 AT 11:05 AM
My 13yo daughter was asking for my help with one issue. Knowing the rule about serial semicolons, she wrote this sentence in an essay:
"Mount Vernon, the home of George Washington; and Monticello, the home of Thomas Jefferson, are some of Virginia's most famous historical sites."
I told her the semicolon should have been a comma because the phrase in question came at the beginning of the sentence, versus after the lead-in about Virginia's historical sites. But am I right on this?
Erika Suffern 27 May 2020 AT 08:05 AM
Your daughter had the right instinct, noting the many commas in the sentence. But the comma is correct because there are two items (Mount Vernon and Monticello), so she has a pair rather than a series.
Jacoby Hickerson 07 June 2020 AT 02:06 AM
Unless my browser is parsing a character wrong, there seems to be a missing uppercase or comma in the following sentence: "Who would object to unambiguous prose? you might ask."
I would expect either "you" to be capitalized or perhaps a comma after prose.
Shelly 12 November 2020 AT 01:11 PM
As per MLA 8, should we use the serial comma in a journal subtitle, such as, XXX: A Journal of Asian Literature, Arts and Humanities?
Erika Suffern 16 November 2020 AT 08:11 AM
Generally don't add a serial comma in the title of a publication.
Chris Montemayor 28 November 2021 AT 04:11 PM
Let us not be afraid to use parentheses along with colons (full disclosure: I just don't like serial semicolons).
In his report, Mr. McCarthy presented on: the annual budget, his plans to hire for three new positions (director of operations, a chief financial officer, and a human resources assistant), the fundraising efforts of the development committee (which expects to meet its goal by the end of the fiscal year), the recent accomplishments of the committees on accessibility, research, and sustainability, and the restructuring of the product development team.
You really don't even necessarily need the colon then, and no matter how you slice it, the sentence is long-winded as hell. (That's its own issue.)
Joseph Davis 14 March 2022 AT 06:03 PM
Does a comma precede direct objects (?) that are followed by a series? For example,
"Definitions are distinguished by numerals, “1,” “2,” and “3,” as applicable."
If not, would it be necessary if I added the word, "the," in front of "numerals?"
Sandi 06 August 2022 AT 09:08 AM
Is the use of a semi-colon appropriate in separating sentence frames in the following sentence:
Use this routine to help students explain whether any of the triangles they drew are
identical copies. Provide sentence frames such as: “I noticed ___, so I ___.”; “This
triangle is/isn’t identical, because ____.”
Jim Wallace 17 October 2022 AT 02:10 PM
As to the necessity of the serial comma (curse the newspapers who need to sell more advertising space), check out this story: https://www.nytimes.com/2018/02/09/us/oxford-comma-maine.html
Clearly, there is precedent for using the comma.
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