Commas Before and in a Series

In American English usage, many writers and editors feel that a comma should precede and with three or more items in a series.

Example: I would like to order a salad, a sandwich, and dessert.

Newspapers and magazines do not generally use this rule as print space is too valuable to use on what might be considered extraneous punctuation. However, print publications will use the final comma before and if it is needed to avoid confusion.

Example:
Her $10 million estate was split among her husband, daughter, son, and nephew.

Omitting the comma after son would have led the reader to believe that the son and nephew had to split one-third of the estate (each receiving one-sixth) rather than understanding that each relative received one-fourth of the estate.

If the article or the existing discussions do not address a thought or question you have on the subject, please use the "Comment" box at the bottom of this page.

87 responses to “Commas Before and in a Series”

katie says: I get the comma part, but why isn’t it Environmental, Health, and Safety Policies?

Katie, it could be “policies.”
T.J., while many people have been taught to exclude the comma before “and” in a series, putting a comma in helps clarify. That’s the whole point of punctuation!

I was taught during my teen years that “and” can already be used as a separator instead of comma. Will it not be repeative if we use comma wiht and at the same time? But if that is the latest innovation now, then i will apply it. Many thanks

Using a comma before “and” isn’t repetitive; it is helpful in letting your readers know that you mean a separate item on your list.

Robert E. Browne says: I bought your blue book and read each of your messages with interest.Thank you! Oloketuyi says:

comma before “and” looks like a new thing in Grammar world. If it is, I would like to be more enlightened, because, for a list of words that is three and above, comma would be used to separate list of the worlds until you get to the last two when you will use “and” to separate them. Thanks

Amanda Leonard says:

When I was in school we were still taugh that the comma should be before the “and” in a series, but style manuals do differ in opinion. Most say it is not necessary but does help clairify things. I as a rule do not use it, and was taught that either way is correct but to pick one and be consistant in using it.

It is a common myth (and practice) to use “and” to replace the comma; however, The Chicago Manual of Style, along with every other authority (American), strongly recommends using the comma to avoid ambiguity.

Dera Williams says:

Maybe in the example given, a comma is necessary in order to separate
Health and Safety but normally, it is correct to write with or without a comma. The key is to be consistent.

Debbie says:

I thought the first one was correct, but that was because I thought the Health and Safety was one publication.

Phillip Dunn says:

i agree with this rule. Leaving the comma out before “and” in a list of three or more items seems to join the last two items, at least to me. For example: 1) I have worked in the hardware, appliances, boys and girls departments. 2) I have worked in the hardware, appliances, boys, and girls departments. Example 1 makes it unclear if there is a departement called “boys and girls” or if they are two separate departments. Example 2 makes it clear that they are separate.

Dera, see my comment above about what The Chicago Manual of Style says. Thanks for writing. freddie says:

After all this year I always use there is no comma before “and”. I think, comma before “and” litle bit over writting. What I mean is, when we are not using comma before “and”, there is no confusion because “and” is explainning the changing of the words or object.

Aishwariya says:

This is known as the Oxford comma. In U.K. English, it would be incorrect to use it while in U.S. English, it is mandatory.

Amer Riaz says:

Commenting on the reply by Phillip Dunn, I suggest the use of & instead of ‘and’ to clarify that two items make up one item of the list. For example:
I have worked in the hardware, appliances, and boys & girls departments. I have been using this technique while writing user manuals.

This is fine for manuals, perhaps, but not for formal writing. Dmitry says:

This is a small discussion I have had with my English teacher in high school recently. She claimed that using a comma before “and” in a title is incorrect (in fact the title of the document was, “Explain, describe and narrate”). I have said that I will prove myself right, and the evidence in this blog is quite sufficient in my eyes. Although, I do have a request. Please clarify whether the comma before “and” applies in ALL contexts or just body of a letter or such. Thank you

Stephanie says:

Jane, While Chicago insists on serial comma, AP specifically does NOT use it. I don’t think this is a cut-and-dry issue. I teach high school English, and the Elements of Writing series (very commonly used) specifies that either is correct.

Stephanie, perhaps this debate will never be resolved. I suggest using the comma before “and” in a series for clarity since there are many occasions when leaving it out causes confusion for readers.
Dmitry, I don’t know what other contexts you are referring to in your question. Please clarify.

Joe Harkins says:

Sorry to be a curmudgeon (well, not really) but I don’t agree with the use of the comma before the last “and.” Many here report that this was taught in school, confirming to me that it is a recent affectation. I can tell you it wasn’t taught in any of the 6 different Catholic grade schools I attended as our family moved around in the 30s and 40s, nor was it taught in the Jesuit prep high school in any of the three languages that were required. Having written professionally (as in “for pay) for hundreds of magazines, newspapers, websites, pamphlets, manuals and commercial publications, I have never had an editor insert that extra comma. (BTW, did anyone here have a problem understanding that previous sentence because it lacks an extra comma?) I do not recall, offhand, ever seeing it in the fiction or non-fiction of any published writers prior to recent times. It remains a mystery for me as to how it got started and an even deeper one as to why it continues.

John Touhy says:

Joe is correct. Not only is the use of a comma before an “and” unnecessary,
it was thought to be incorrect in the finest schools and universities for decades, and through the 1970s. There is no compelling reason to accept an incorrect usage.

Our Rule 1 of Commas acknowledges the option of omitting the Oxford comma before and as long as omitting the comma does not cause confusion. A lot of authorities going back to the mid-20th century champion the Oxford comma, and most serious books employ it and have for decades. It is neither “an incorrect usage” nor “a recent affectation.” Please see the following blog from 2013: The Oxford Comma.

As further evidence of the importance of the Oxford comma, see our blog post Lack of Commas Costs Company Millions in Dispute. This emphasizes the point we made in our response of September 23, 2014, above: you may omit the Oxford comma “as long as omitting the comma does not cause confusion.” And, we should add, “and potentially cost you millions of dollars.”

Jenny Rodriguez says:

Hasn’t that rule fluctuated? I remember the Comma in after the :”and” then for awhile, then it was out after the “and.” I have a question re: the period after or before the second quotation mark. I can’t stand seeing “floating periods”! (or exclamation marks, for that matter) Ex: He was a “true, blue friend”.

Ashley says:

I disagree with our comma tip when it comes to listing things. In Associated Press style, you do not add a comma before AND. It might not be relevant to your audience, but I thought I would mention it.

Richelle says:

I’ve always read, and taught my students, that the comma before and wasn’t necessary; actually, I believe it would be correct both ways—with or without the comma.

Heather Hunter says:

My four yr college degree was in English, and I was taught throughout grade school, junior high and high school that you do NOT need a comma before the word “and” as that is what the word “and” is for. However, if you are changing subject matter, then a comma would be warranted.
I am the Sr. Tech in our Publications Dept here in a large school district, and I receive masters with and without the comma before the word “and”. I think it’s 50-50 now, but mostly older teachers leave out the comma. I instruct my four children to NOT use the comma; it’s redundant.
Thanks for your informative and helpful weekly email newsletter.

Brian E. Wood says:

For heaven’s sake! Has no-one ever read (or heard of) G.V. Carey’s ‘Mind the Stop: A brief guide to punctuation’? 1st publ. CUP, 1939; revised 1958
Pelican Books, 1971; reprinted in Penguin Books, 1976 Copyright : Cambridge University Press 1958 The late, great GVC addressed this ‘problem’ with genius and killed it stone dead. READ HIM, (!) AND STOP ALL THIS TIME-WASTING NONSENSE!

Lance says:

If, for poetic reasons, one wanted to write “Athenians and Trojans and Spartans have long been…”, would you still insist on commas before each “and”?

Lance, I would not use commas to separate “Athenians and Trojans and Spartans have long been…” Brian, how about sharing G.V. Carey’s response so that we know what he said? Heather and everyone else who disagrees with using the comma before the last “and” in a series: I’m sticking with my recommendation to use the comma.

Debbie says:

THANK YOU! This has always been confusing to me. I’m delighted to know the rule so I can finally punctuate accurately.

ravi bedi says:

Philip Dunn has given explicit example of Girls’ and boys dept., and Girls’, and boys dept. It clarifies what Jane proposes.

Good point! ravi bedi says:

Ref. last examples above. ” to my parents, Brad, and Janet”…meaning Brad and Janet other than the parents?
“to my parents, Brad and Janet”…meaning Brad and Janet are her parents. Am I right?

shejo inasu says: This is a new information that was useful.
Thanks.

Putting a comma before an “and” isn’t proper English! But this is America… where we never teach anyone to do things properly. Instead, we “dumb” things down to make them easier for everyone. No wonder this country is going down the tubes.

Kristina says:

What in the WORLD are you talking about. The “comma before and” you’re referring to is called an “oxford” or a “serial comma” and is used depending on the industry. If you work in sciences, engineering, scholarly, or pretty much any industry that warrant clarity due to the complexity of the content, the oxford comma (the one you’re saying is not needed and is dumbing down Americans) is ESSENTIAL. The only industries that believe in removing it are journalism and the like because they need to keep their text as brief as possible to fit as many characters on the page as they can. But, actually removing the comma in a list before the word “and” can make sentences extremely unclear, and it has actually led to full-on lawsuits where workers won millions of dollars because their contracts didn’t include the oxford comma, and as such, their overtime payment clause was unclear. If you choose not to use an oxford comma, you are risking a lack of clarity.

See our blog post Lack of Commas Costs Company Millions in Dispute for more information regarding the lawsuit mentioned by Kristina. This surely is a testament to careful use of proper grammar and punctuation.

Who says that putting a comma before “and” isn’t proper? If this country is indeed “going down the tubes,” in my mind, the comma before “and” doesn’t rank with media and government attempts at “dumbing” us “down.”

Adam G says:

I usually use the “comma before the and.” But in some situations, is it better to not use the comma? I work with advertising, marketing, and signage materials and notice that many professional pieces deliberately drop the comma before the and; it seems to be done by design. Is it possible that the “comma before the and” is not desired or needed in certain situations, like advertising or signage?

If a customer doesn’t desire the comma before “and,” then leave it out, of course. However, I find that people are not often aware of this rule and are happy to have the comma added for them.

Tracie says:

I am an editor, and I believe that using a comma after “and” is most beneficial for a variety of reasons. As a background, I grew up being taught in elementary school through high school you use a comma in a series. For my editing classes in college, we followed the Chicago Manual of Style. The latest edition of Chicago (which is one of the most often used style guides) recommends using the oxford or serial comma. The use of the comma is most helpful to delineating what constitutes a separate entity in a list and also serves to avoid ambiguity. The AP Stylebook, most often used for newspapers and other media, does recommend the comma be omitted before the “and.” I believe this is because AP style focuses more on brevity. Newspapers and the like often have limited space for publication. An extra comma adds extra space to the typesetting. However, I still recommend that for most purposes a comma be used before “and” in a series to avoid ambiguity. That is one of the chief purposes of punctuation and one of the chief rules of writing. Strive for clarity and avoid ambiguity.

Bravo! Ditto to all your thoughts, Tracie. Adam G says:

Thanks for the info. I also think that the brevity idea (from AP Stylebook) may be applied to commercial advertising, graphic design, and marketing work for commas before and. It seems like a lot of comma exclusions take place in those situations, for space saving and also possibly aesthetical reasons (from what I’ve seen). Anyone else work in those fields?

NK, who defines proper English? I would think Oxford University is a fairly authoritarian source on the matter and they say to use the comma – despite the fact that its use is less standard in Britain and the US. There are cases where the Oxford comma is ambiguous and cases where its omission is ambiguous. Molly, a painter and a musician…. Is that one person or three?
My dog, Ruffles, and a cat…. Is ruffles my dog or are there three seperate animals? Many style guides say to use the Oxford Comma. I would not call following these style guides incorrect or lazy. Most newspaper authorities (AP, New York Times, etc.) request to not use the comma for space reasons. This is not a good reason to set a grammar precedent. As for the Oxford comma being a new invention, that is just plain false. The debate about whether to use it or not has been around for a long, long time. I learned to use it in the ’80s and I was being taught be 80 year old teachers who wanted things to be done the way they did it as a child. From my understanding the sentiment on this issue has changed several times over the years.

Julie says:

My main reason for searching this site was to determine if the comma before the and is needed in a list of names. I create birth announcements and at the bottom we list the names of the members of the family such as Victor, Melissa, Kevin, Jenna, Olivia, Gabrielle and Hunter. I have always left out the “oxford” comma, but many of my customers ask me about this when they view their proof. Always the comment is “I think there should be a comma before “and”, but I am not sure” I have always told them the “and” replaces that comma (and thought it did in every instance), but after reading all of the above wisdom, I am going to amend my stance and say that it is used when the last two words in the series could be inadvertently joined in the reader’s mind by the word “and” instead of separated as intended. Great examples above. I was taught not to use it, I graduated high school in 1981 and college in 1986. My son is in 5th grade and is taught to use it in every instance. For names, I think it is unnecessary, and feels redundant, but for a list of objects or elements that could be joined – boys and girls, health and safety, the dog, and parent examples, (vs. the dog and parent) I think we have to use it if indeed each is a separate element. Conversely if the last two in the list are joined, my parents, Bart and Jean, then of course we’d leave it out. Thanks everybody!

Every school text I ever used said to use a comma before every item in a series of 3 or more. I have my college writing book right here, and it says to use the comma before and. The exception to the rule is in newspapers and magazine because they like to save space. The comma helps with clarity. The car lot purchased some new cars. The cars are red, blue, green, black, and white. If you write- The cars are red, blue, green, black and white. This looks like the last car is a 2 tone car that is both black and white. This is confusing. USE the comma!

I agree completely! US History Notes says:

Just wanted to say thanks for the great post ! Found your blog on Google and I’m happy I did. I’ll be reading you on a regular basis ! Thanks again.

Thank you, Donna! deedee says:

I have a question about sentences.
What is the correct puntuation for this sentences? Sentence:
(Please help me wash the dishes) is this sentence a statement or question?
Please help me. My daughter has just started third grade and is having trouble with this sentence.
If anyone can help,pls do.
Thanks a lot.

This is a polite request, not a question; Therefore, a period, not a question mark, is used.

My daughter is doing an assignment on commas. She has various types of sentences involving commas. The following sentence puzzles me.
The setting is London England Christmas Eve 1843 in various offices and homes.
I know that a city and state have to be separated by a comma, but I’m not sure about the rest of the sentence. What is the comma rule called that is used in this instance?
I can use the help. Thanks!

We believe there are two acceptable ways to write this sentence.
1. Combining Rules 5b and 6 of Commas (and extending the rule for city and state to include city and country): The setting is London, England, Christmas Eve 1843 in various offices and homes. OR
2. This could be considered “a series of three or more,” and therefore would combine Rule 5 of Commas with Rule 4 of Semicolons: The setting is London, England; Christmas Eve 1843; in various offices and homes.

Thank you so much for this!! I’ve been helping my 11 year old with homework for a few years now and I’ve always explained the comma before and in a series is wrong because I did not learn to use it this way but with all of your help and info I’ve been proven wrong. Bill and ravi bedi’s examples were a huge help in realizing the difference and how there can be confusion without the comma before and. Be open minded people the comma before and in a series is by all means needed, although not required, but it should be.

Susan St. Marie says:

when listing multiple people and titles, is it correct to use a comma or semi-colon?
i.e. John Smith, M.D., P.I.; Mary Jones, N.P., Sub-I; Jane Johnson, study coordinator;
Thank you.

Rule 4 of the “Semicolons” section of Grammarbook.com says, “Use the semicolon to separate units of a series when one or more of the units contain commas.” Since your list has several units that contain commas, the use of semicolons adds clarity.

Susie says:

I appreciate the information here and agree that often that comma before “and” is helpful, so I use it. But I have another question regarding a series–what do you do with a series in the middle of a sentence? Do you always add another comma after the third item, or would that only be if the series is considered nonessential?
Examples:
All monies in checking accounts, money market accounts, and savings accounts shall be considered to be cash equivalents.
The prosecutor argued that the defendant, who was at the scene of the crime, who had a strong revenge motive, and who had access to the murder weapon, was guilty of homicide. (From Purdue OWL site) Thanks!

You would only add a comma after the third item if the series is a nonessential appositive, as is the case in your second example.

Angel says:

Question:
In a closing of a memoriam/”signed by” (“Sadly missed by”)
Your wife, Karen and your family
Your wife Karen and your family
Your wife, Karen; and your family
when Karen is the wife? – Which to use?

Our Commas, Rule 11, states: If something or someone is sufficiently identified, the description following it is considered nonessential and should be surrounded by commas. Therefore: Your wife, Karen, and your family

Steph says:

I am British and was taught to omit the comma before and, when in a list. The main time we can use a comma before “and” etc, is when inserting between two or more independent clauses. For example, “It’s been raining all night, and the roads are slippery.” If you omit the “and”, the two clauses could function as separate sentences and a comma can therefore be used. In terms of lists, shouldn’t one always put “and” before the last item? If this is so, the sentence, “The cars are blue, green, black and white” is not confusing. There are white cars and black cars. If, however, there were cars that were black and white, surely the sentence would be, “The cars are blue, green and black and white.” In this instance it could be argued, in British English, that the Oxford comma could (but not should) be used before the first and. The names are very good examples of using commas, at one’s discretion, in order to clarify. This is definitely not the case in a standard list in British English though. I am fairly young and was taught grammar at school, as well as at home, and this is not, in my experience, modern practice in the U.K. Highly confusing I must admit! Jane, the responses regarding semi colons have been most helpful. As far as I am aware, the U.S. and U.K. rules are the same for this. Phew!

In order to avoid confusion, we are in agreement with The Chicago Manual of Style’s rule which says, “Items in a series are normally separated by commas. When a conjunction joins the last two elements in a series of three or more, a comma—known as the serial or series comma or the Oxford comma—should appear before the conjunction.” Chicago strongly recommends this widely practiced usage, blessed by Fowler and other authorities, since it prevents ambiguity. If the last element consists of a pair joined by and, the pair should still be preceded by a serial comma and the first and (see the last two examples below). She took a photograph of her parents, the president, and the vice president.
Before heading out the door, she took note of the typical outlines of sweet gum, ginkgo, and elm leaves.
I want no ifs, ands, or buts.
Paul put the kettle on, Don fetched the teapot, and I made tea.
Their wartime rations included cabbage, turnips, and bread and butter.
John was singing, Jean was playing guitar, and Alan was running errands and furnishing food.” Therefore, in American English, your example with black and white cars is written as: The cars are blue, green, and black and white.

Heather says:

I note you rule (Rule 2) under Commas stating to use a comma to separate two adjectives when the word “and” can be inserted between them. What about colors? i.e. A white, one-floor trailer – is this correct? “The house had a blue tin roof? “He was a tall, white, thin male.” “She was a 48-year-old white female.” Is there an actual rule advising in the use of colors to know when you should use a comma and when you shouldn’t in sentences with more than one adjective that includes a color? Also, for example, when describing a person, or shirt (i.e. she wore a blue, collared, long-sleeved blouse.)

Colors are adjectives, therefore our Rule 2 under Commas applies to colors. There is not a separate rule specific to colors. a white one-floor trailer (No comma is necessary. You would not say “a white and one-floor trailer.”)
The house had a blue tin roof. (No comma is necessary. You would not say “The house had a blue and tin roof.”)
She was a 48-year-old white female. (No comma is necessary. You would not say “She was a 48-year-old and white female.”) Our Rule 1 under Commas applies to your other examples. “To avoid confusion, use commas to separate words and word groups with a series of three or more.” He was a tall, white, thin male.
She wore a blue, collared, long-sleeved blouse.

Nancy says:

In closing of a memoriam, are all commas used correctly here?
With love from, wife, Mary, and daughters and their families
Should daughters and families be capitalized?

The words “daughters” and “families” should not be capitalized. No commas are strictly necessary in your sentence. But with all respect, we recommend rewriting it. The stand-alone “daughters” looks odd to us. The sentence seems to be avoiding saying “your” or “his,” as in “With love from your wife, Mary, and your daughters and their families.”

Introductory words followed by series: In the following sentence, can you add commas to the series following “namely”? I’m not finding any rules supporting commas in this instance. Sentence: When you went out, you could see evidence that it had been raining, namely, that the cars were wet and people were wearing raincoats and there were puddles on the ground. Many thanks.

Our Rule 16a of Commas says, “Use a comma before and after certain introductory words or terms, such as namely, that is, i.e., e.g., and for instance, when they are followed by a series of items.” The second that and the first and are unnecessary. Our Rule 2 of Semicolons says, “Use a semicolon before such words and terms as namely, however, therefore, that is, i.e., for example, e.g., for instance, etc., when they introduce a complete sentence. It is also preferable to use a comma after these words and terms.” Therefore, we recommend the following:
When you went out, you could see evidence that it had been raining; namely, the cars were wet, people were wearing raincoats, and there were puddles on the ground.

Jill Keogh says:

In response to your grammar posting about comma usage in a series i.e., A, B, and C versus A, B and C The correct answer is it is an absolute function of the style guide you are instructed to follow. The comma after the B is academic style and was the way many of us were taught in school. However, we were also taught in school decades ago to drop the comma if following AP Style Guide and other guides. Newspapers did so to save money on the ink originally (we were even shown the math of the savings). So, the answer is both are correct provided you are consistent in the guide you are following.

Aadhithya says:

I do not know which kind of comma, or commas should be used in the following sentence, or if comma/commas should be used at all. Please help me with it The software supports audio and video editing for small and large files. (The software here allows both, audio and video editing.) Yes, it can be rephrased, but a solution without doing it will be appreciated. Thank you in advance.

No commas are required in your sentence. kraftyiam says:

Which is correct:
1a) My daughters, Alice, and June OR 1b) My daughters, Alice and June
2a) We live in New Brunswick and love it OR 2b) We live in New Brunswick, and love it
3a) Daphne, also known as, Anna OR 3b) Daphne, also known as Anna Thank you.

The rules for this post apply to sentences containing three or more items in a series. That is not the case with any of your examples. Your first example contains an appositive; therefore, two answers could be correct. Please see Rules 5 and 6 of Commas, as well as our post Commas with Appositives for a complete explanation.
1 My daughters, Alice and June, if you have only two daughters OR
My daughters Alice and June if you have more than two daughters Your second example does not require a comma, as there is no independent clause after and. See our Rule 3b of Commas for more information. A period is requred at the end, since it is a complete sentence.
2) We live in New Brunswick and love it. Your third example contains a nonessential phrase; therefore, a comma is necessary. See Rule 5 of Commas for more information.
3) Daphne, also known as Anna,

Marty says:

Good piece. Thank you. As you said, punctuation is for clarity, so using the comma makes sense. I proofed for the State of Montana for a few years, and the comma before “and” was mandatory for the State Code books (State laws). Although optional elsewhere, not using the comma can sometimes be confusing, whereas using it can never lead to confusion.

Laura says: What about a card signed:
Love, Tom, Mary, Joan, and Isabelle?

If you have room, we recommend the names be placed on a separate line:
Love,
Tom, Mary, Joan, and Isabelle

Jane E Rocque says:

Use of the word “and” in a different context: Why do most TV weather persons state e.g. it was 100 and eight degrees today? They should be stating that it was 108 degrees (one hundred eight degrees), no “and.” I taught math for a short time and always told my students when writing a check to only use the word “and” before the cents section.or as in the numerical amount suggests such as $108.08 would be One hundred eight dollars AND 8/100 or 8 cents. Am I correct in this?

We agree with you (see Rules 8a and 8b of Numbers). Audrey V. Buffington says:

The comma before the last item in a sequence can be very helpful. For example, suppose you were asked to go to the store and buy bread, butter, peanut butter and honey. Are you going to buy 3 items or 4? Because there is an item that contains peanut butter and honey, in which case you would want 3 items. But if you wanted 4 items, then a comma is critical.

We are proponents of the Oxford comma because it can’t help but clarify.

Are commas necessary when referencing a person’s multiple occupations? For example: The evening will include a walk-and-talk led by the poster expert, and gallery owner, Tim Smith OR The evening will include a walk-and-talk led by the poster expert and gallery owner Tim Smith. Thank you!

This post refers to three or more items in a series. Your sentence contains two items and an appositive. Our post Commas with Appositives says, “An appositive is a word or word group that defines or further identifies the noun or noun phrase preceding it.” The appositive in your sentence is Tim Smith. The noun phrase the poster expert and gallery owner probably is not a precise identifier; therefore, Tim Smith is an essential appositive. No commas are necessary. (However, if everyone knows that Tim Smith owns the gallery and is a poster expert, then his name is nonessential, and a comma should precede his name.)

Kimberley Edgar says:

Thank you for this treatment of comma before conjunction in a series. It was drilled into us at the Medill School of Journalism at Northwestern University that there is no comma before “and” or “or” in a series of three or more. I have practiced this as an award-winning journalist for years without question or challenge from my colleagues. However, more recently, I have been concerned as my children have been taught to insert it (extraneously, in my opinion) in their English and Language classes at school. I have been combing through various resources of mine looking for the genesis of this rule, and yours is the only one I’ve found that includes this structure with a worthy explanation of how it came to be. Thank you!

GrammarBook.com says:

As we mention in our Rules for Commas, most newspapers and magazines drop the Oxford comma in a simple series, apparently feeling it’s unnecessary. The Oxford comma is more common in formal publications (e.g., books, governed more by CMOS) and less prevalent in journalism and mass media (governed more by AP). Teaching the Oxford comma in school prepares children for a more-formal approach to writing style, which is a better starting point for learning later how style can be varied as opposed to learning less-formal style and learning later how to make it more so.

John Carroll says:

It certainly depends on which stylebook is being used. I have always preferred the Oxford comma to avoid any confusion.