On list groupings and the correct use of commas

Why does it seem that nobody knows the correct way to end a comma-delimited list? Did they stop teaching this after 1990 or something? Let’s review, shall we?

First let me explain the philosophy upon which the correct use of “commas in lists” rests. It’s another topic that I realize they almost definitely stopped teaching after 1980: mathematics. Take the following expression:

1 + 1 × 3
Grammar must have algorithms or else it’s useless.

If you studied mathematics in school you should remember the algorithm that is used to resolve it. There are no special characters in this expression, so we evaluate any division or multiplication first, then addition and subtraction, and we go from left to right. So this expression — in your mind — looks like this:

1 + whatever I get when I multiply 1 and 3

The expression evaluates to 4, of course. To make the expression easier, you could add brackets or parentheses:

1 + (1 × 3)

That equals 4 as well, and is, in fact, logically equivalent to the first expression.

Let’s mix it up a bit! Change the arrangement of the parentheses to this:

(1 + 1) × 3

This is completely different! See? Our rules tell us to evaluate values inside parentheses or brackets first! So this expression — in your mind — looks like this:

first get the sum of 1 and 1, multiply that sum by 3

Do you see why this matters? This expression contains the exact same values and the exact same logical operators (the plus sign and the multiplication sign) but it does not evaluate the same way! This expression evaluates to six. In the algorithm used to solve equations like this, the parentheses have precedence over any other logical operators.

Now this is where it gets exciting! The rules of grammar — I know for a fact that they stopped teaching these in 1990 — follow similar algorithms! I know, I know. “That’s crazy talk,” you say. But it’s true. Grammar must have algorithms or else it’s useless. A language that has no rules, well that’s no language at all. People are always griping and complaining to me about how flexible the English language is. People say that there are no “rules” in English. That’s not true. There are rules. It’s just that we — humans — are smart enough to understand each other in spite of the fact that we break the rules.

Some of you might be thinking, “Hey! This is sort of like the web standards thing that Zeldman is always trying to tell us!” That’s correct. The hypertext markup language (HTML) upon which the web is based has rules. It has rules in the same way that the English language has rules. When your browser looks at a web page, it reads the HTML — which is pretty ugly and hard to read — and converts it into something to display to you. This is analogous to your ears and brain converting the words coming out of my mouth — which sound pretty strange if you really think about it — into a comprehensible thought. It’s analogous to your eyes and brain converting little squiggles on a piece of paper into a comprehensible thought. Get it?

Our brains are really smart. I’m not kidding. Take the coolest, fastest, grooviest supercomputer on the planet. Even if it can beat me at chess, I’m still smarter. So are you. Brains just work better than computer chips. They might not always be smarter than computers, but as of right now there aren’t any computers that can be considered smarter than a brain. A web browser reads HTML and it tries to be forgiving. What does that mean? It means that if the person that wrote the HTML forgot to close a tag, the browser will try to compensate for you and not destroy the web page before it displays it. This is similar to me not putting my fist through someone’s face when they say, “impacting.” Impacting should not be something that is allowed. An “impact” is a thing.

BOOM! Look! A meteor just landed on that Cadillac! Did you see the impact?

At what point was anything “impacting”? You maybe could argue that for a millisecond the meteor was “impacting” the Cadillac. (I’d argue that you are an ass. But that’s not the point.) An impact is a thing; it’s not a happening.

But we are a forgiving people and we have forgiving brains. So when you talk to me you say, “Wow! Did you see that new movie with Ah-nuld? It’s really impacting our society!” I am forgiving. I don’t freak and punch you in the face and exclaim, “You sound like a complete moron, you jerk.” No. My brain takes the senseless noises you are making and converts them into something that makes sense. My brain imagines that you said, “Wow! Did you see Collateral Damage? It’s really having an impact on our society!” My brain does this faster than you can remove your hand from a burning hotplate. So does yours. When you touch something unbearably hot, your hand jumps away even before your brain has a chance to realize you’re scalding yourself, right? The same thing is occurring here. Our brains convert the idiotic drivel flowing from each other’s mouths into sensible thoughts without even letting us know it’s happening!

This is important. Why? It’s important because it takes brain-power to do that conversion. You have lots of brain-power. You have so much brain-power that you hardly even use most of it. For all intents and purposes we can consider your brain-power unlimited. (The web standards project is trying to get people to follow the rules because computers do not have unlimited brain-power. It takes time and processing power away from other projects when your computer has to untangle poorly-written HTML. Get it?)

How does all this relate to comma use? Commas and semi-colons and parentheses — , ; ( ) — are logical operators in written English in much the same way that they are logical operators in mathematical expressions. Here is a list of people:

Jim, John, Jack, Jeff and Jeremy

The commas are there so we know that there is a separation between the items in the list. The “and” tells us that we are about to see the last item in the list. Correct?


You may want to think that that is what these mean. But you’d be incorrect. What has happened here? Why am I mad? Where is the problem?

The problem is that commas are required to separate each item in the list! There is no comma between Jeff and Jeremy. According to that list, Jeff and Jeremy are only one item. That list would look like this (to someone analyzing it properly):

  • Jim
  • John
  • Jack
  • Jeff and Jeremy

This might not seem important to you at all. But if this was a list of who was going to get an extra $100 in his paycheck, you can bet it would be important to Jeff and Jeremy. According to this list they are only going to get $50 while the other guys are getting $100. A list needs that last comma before the “and” (or before an “or”) to properly delimit the items at the end of the list.

Jim, John, Jack, Jeff, and Jeremy

The above example would let each guy get $100.

The cover of this week’s Sports Illustrated ignores this rule. Here’s what it says:

Living large and holding forth on everything from his golf, money and politics to Michael Jordan, TV Sports and Enron

The cover is describing the topic of an interview with Charles Barkley. This is misleading, though. This tells me that I am going to read about the topics in two lists:

  • golf
  • money and politics


  • Michael Jordan
  • TV Sports and Enron

The interview doesn’t devote more time to golf or Michael Jordan than it does to the combined topics of “money and politics” and “TV Sports and Enron”.

Get it? I know that the interview doesn’t devote more time to golf than it does to money and politics because I read the article. But if you’re designing the cover, do you want to depend on me to translate your bad grammar? Wouldn’t you rather make it easier for me to understand? I’m reading what you wrote. Why should it be my responsibilty to convert it into something meaningful? When people communicate it’s the responsibility of the person who wants to be understood to make himself clear. Why? If you expect people to understand you even if you don’t make sense, you have nobody to blame when you’re misunderstood but yourself.

But that’s just my opinion. If you disagree with me, tell me why. (Just remember that if I don’t understand you, though, it’s not my fault.) Maybe this is something that only really makes sense to computer programmers. A computer is not forgiving and I can get mad at it when it doesn’t understand what I’m trying to tell it. But won’t I sound pretty silly if I scream at the monitor for not understanding me?

There are 32 comments on this post

  1. Amen, brother David! Preach on.

  2. Now I know what you do at work.

  3. I’m currently unemployed, Beavis. I’m looking for a job, though! Someone hire me!

  4. i have been saying the same thing (about commas and grouping) for years, and no one believes me. my teachers get horribly angry when i correct them on this.

  5. The comma of which you speak was deemed obsolete in writing for the mass media, specifically newspaper writing. As if that isn’t bad enough, it somehow made it’s way into the mainstream.

    Correct: I enjoy lagers, pale ales, and black and tans.

    Incorrect: I enjoy lagers, pale ales and black and tans.

    This made me dizzy.

  6. It was “deemed obsolete” by whom?! Do you mean to tell me that they are actually teaching this *incorrectly* in schools now?! Oh good grief!Please don’t hate me, Lone Ranger, but you used it’s when you should have used its.

  7. Or for a lighter view on the subject: “Serial Comma Stalks Grammar Community”. 🙂

  8. It would be hard to believe, I know I wouldn’t believe it, but that was a little joke/quip/gag/jest. Grammar and usage being the topic, I thought it would be appropriate. Humor hasn’t always been my strength.

  9. The difference between the two examples you is purely stylistic and, according to many grammarians, both are correct. By using a comma before “and,” you have chosen to follow the Modern Language Association’s rules of grammar. Not using a comma before “and” would follow the grammar rules set forth by the American Pschological Association. Journalists in print media use APA to save type space. APA is more succinct in it’s use of punctuation, therefore allowing for more words on a page.

  10. Amanda,I would argue – in fact, I did argue! – that the difference is not, as you say, “purely stylistic.” I have not chosen to follow the MLA guidelines. In general I think that the MLA is full of poop. I disagree with so much of the MLA guidelines that it would be laughable if it wasn’t so pathetic.I have never heard of the APA, but apparently they subscribe to the belief – held by so many backwards-thinking fools in America that it’s depressing – that it’s better to do something quickly and easily than it is to do it correctly and logically.I’m sorry, but I just can’t agree with that sort of thinking. I know I’m tilting at windmills and all that, but it’s what I do.Please note that I am not personally attacking you or your comment. <grin>

  11. Well sir, while you are not wrong in your interpretation of comma usage for lists of series exceeding two items, you are not implicitly correct. Regardless of the standard, the rule in North America generally is as follows:

    Comma usage is in some respects a question of personal writing style: some writers use commas liberally, while others prefer to use them sparingly. Most modern North American style guides now recommend using fewer commas rather than more, so when faced with the option of using a comma or not, you may find it wise to refrain.

    For instance, the use of a comma before the “and” in a series is usually optional, and many writers choose to eliminate it, provided there is no danger of misreading:

    We bought scarves, mittens and sweaters before leaving for Iceland. (comma unnecessary before “and”)
    We ate apples, plums, and strawberry and kiwi compote. (comma needed before “and” for clarity)

    Additionally, in a formal paper if you use one style or the other you must be consistent thoughout the document. Since I thought you are an English major, I am surprised you don’t know this. If your concern is putting lists in Excel from a comma delimited list then all the commas are indeed required. But the “and” would likely cause some problems, would it not? Writing, speaking and computer programming are still different things. It doesn’t take a rocket scientist to figure this out. But just in case I will confirm it for you.

  12. David – Thank you! You are preaching to the choir. English DOES have rules and they should be followed as much as possible. Problems arise when people use solecisms — be it in spoken or written language, or in HTML. Either it doesn’t work (you don’t understand what the person is trying to say, or what the browser gives an error message) or it is not supported universally (some people understand what is being said, or only some browsers will load the page as written).

    I have always been one to argue the “and” issue. I can remember arguing it in the seventh grade with Ms. Flaum.

    The other day we ran an article in the paper titled “Red, White, Blue and Muslim, Too.” Yuck. I go through this torture every day — I have to consciously change my way of thinking about commas to conform to this AP style. Unfortunately in AP Style, we do away with the comma before a conjuction in a series. For example, AP style: This morning I ate bacon, eggs, toast and cheese. So one would think I had bacon and eggs and “toast and cheese.” But no, I had bacon, eggs, toast, and cheese. (Not really, but it sounds good right now.) Or how about our flag? It is red, white, and blue. Three colors. Not red, white and blue (one part red, one part shared as white and blue).

    My sister has written papers in the APA style because she works in that field. I used MLA in college. I am now having to “reprogram” my brain and use AP Style. Why are there so many different styles? Of course the different styles are going to integrate into our “mainstream” language and distort it. Wouldn’t things be much simpler if we all used one style of our common language (think Academie Francaise)?

  13. It would depend whether you are English or American as well. Proper English usage does not have the last comma (before the ‘and’). It has never had that: it is an Americanism. I love to add a little more confusion. 🙂

  14. Thank you, thank you, and thank you.

    Great argument on comma usage. It’s amazing, startling, and disappointing how so many otherwise seemingly competent writers are ignorant, stubborn, and flat out stupid when it comes to this issue.

    An argument I had recently with a writer (who supports incorrectly eliminating the last comma in a list) is that “English is a progressive language. You don’t need the last comma in a list of three or more items.”

    I tell him, “Yeah, well, Ebonics is progressive to, you fscking moron.”


  15. Pedantic, prescriptive bastard

  16. I’m using HTML tags!! HA HA

  17. damn….

  18. I think you are correct, but for the wrong reason. Punction is not logical shorthand. Punctuation exists to imitate speech. A comma is a pause, a period is a full stop. Parentheses indicate an aside. Semi-colons and colons probably exist to separate related sentence fragments (not strictly imitating speech). If you read lists with this in mind, you will see that a comma before “and” in a list more closely mimics speech. That’s all there is to it, and that is why you should use a comma before “and.”

  19. Sometimes I use words that arn’t real, but not on purpose. The teachers always correct me.

  20. Thank you David for clarifying my sanity. I was taught the “correct” comma usage years ago, but currently have professors disputing this in papers I have written recently. You are my hero.

  21. I am in complete agreement with you, but unfortunately there are more than a few manuals of style that do not agree with us. From one: “Put commas between the elements of a series but not before the final ‘and’, ‘or’ or ‘nor’ unless that avoids confusion.”


  22. jeez. i thought i was crazy adding the comma before the and. no one does it anymore, but i KNOW they taught that you were supposed to in elementary school.
    what if someone said that they had three marbles. the colors were pink, black and white. how unclear is that!?


    ann marie

  23. Finally! Some justification! I can’t believe that I actually searched the Internet looking for assurance. The “incorrect” way of using a comma is so common in the workplace. How sweet it is…..VICTORY!


  24. You’re wrong. You’re American, you’ve got bigger battles to fight before figuring out the Oxford Comma. It’s not about ‘grouping’, it’s about flowing speech and breathing. Do you say “This is black, and white” ? No, no comma there. If you think the English language is about rules and strict adherence, you’re gravely mistaken.

  25. You think you’ve got problems? I’ve just been involved in a job analysis exercise where the phrase, “where persuasive, motivational, negotiating, training, empathic or re-assurance skills are required” is, I’m told, supposed to mean either all the listed skills are required, or alternatively, that all the comma-delimited skills are required except for the last one, which is sufficient by itself!

  26. The Associated Press style guide says don’t put the comma. My mom says it’s optional. My dad says put the comma. I like your rationale. What about students taking standardized tests — will they be penalized for putting (or not putting) the comma before the conjunction? This is the only instance I can think of where it really matters…

  27. My brother says he goes by the Associated Press Stylebook, which says …

    comma (,)

    IN A SERIES: 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.

  28. A great site. I was taught (by a very strict English grammarian) that just as you write in mathmatics, a list should include the comma before the ‘and/or’. This is the style that I utilize. However, the same professor of English also acknowledged that some style guides do not require this comma. There is no ‘true’ answer to this question that has been a frequent topic of discussions. The only solution that my Grammarian colleagues have determined… regardless of the style you decide to utilize in your document… you must be consistent and use that style throughout the entire text.

  29. I’m currently a teacher for the fourth grade and taught third grade last year. One of our objectives is to teach proper comma usage and placement. According to our state’s requirements, students are to place the comma prior to the word “and.” It would be correct to say: I ate pizza, corn, and bread. My students recently discovered that in our phonics book the editors have written sentences in a series without the comma before the “and.” Example: We went shopping, played on the playground and ate lunch. We had to discuss how it depends on your audience and what you are writing. I require my students to put the comma in before the “and” to make it clear what we are saying in our writings. But, I have also taught my students, “When in doubt, leave it out!”

  30. Oh, goodness, thank you!

    I was honestly beginning to think that I was losing my mind, as I was seeing grouped things everywhere with no comma before the last item.

    I have no idea of what’s happening to our world — simple grammar rules are being ignored by self-acclaimed “grammer experts”.

    This was quite informative, and saved me a bit of money from not going to a shrink.

    Thank you for shedding some light on our English language– and correcting those moronic writers behind mass media.

  31. […] matter how annoyed I am by Oxford University’s egregious behavior, imagine the frustration of THIS guy — he was bewailing the incorrect usage of commas over NINE YEARS […]

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