What punctuation mark has caused more problems than the comma? Rhetorical question, you say? What’s rhetorical? you ask. I’d tell you if I knew. But today I’d like to discuss the most abused, misused, overused, and misunderstood punctuation mark of them all: the comma.
Author Amy Einshon calls commas the “copyeditor’s nemesis” because comma misuse is one of the toughest grammar nuts to crack. Yes, commas can be difficult, but with a little effort, we can master them (or die trying).
The comma is a delicate punctuation mark—some would say even dainty. It doesn’t bear the heavy burden of ending sentences (use the period for that), of marking astonishment (employ the exclamation point!), of asking (roll in the question mark), or of pausing between independent clauses without using a conjunction (hand that one to the semicolon). Its duty is lighter but no less important. To put it simply, the comma indicates a slight pause. But not every place we naturally pause in written or oral communication requires a comma. And sometimes where we don’t pause, there a comma must go. How can we solve this confusion?
Rules of grammar seem so restricting, so schoolmarmish. But they do help us make sense of written communication, so let’s consider eight basic comma rules. If we master these eight rules, we are well on the road to mastering our very souls. Aren’t you glad you’re reading this?
- Use commas to separate three or more items in a series. If Strunk and White felt it was important enough to make this the second of eleven “elementary rules of usage” in their classic work, The Elements of Style, I can make it the first of my comma rules. Here’s an example: “Georgie Porgie celebrated National Punctuation Day with his four siblings: George Ann, Porgette, Pudding, and Pie.” Notice how I separated each name in the list with a comma, including one before the final name, Pie. That final comma always comes before the conjunction—in this case, and. It’s called a series (or serial) comma, or, if you really want to sound highbrow, an Oxford comma.
- Use a comma to separate independent clauses (i.e., clauses that can stand on their own as complete sentences) that are joined by a coordinating conjunction. The most common coordinating conjunctions make up the acrostic FANBOYS: for, and, nor, but, or, yet, so). Before you go running for a Greek lexicon because this all sounds like, well, Greek, let me illustrate with a biblical quotation, which should be acceptable to half of you. In a recent sermon, our pastor read from Luke 1 about the angel Gabriel’s visit to Mary announcing the birth of Jesus. (It’s okay to do this in May.) “You will be with child and give birth to a son, and you are to give him the name Jesus” (Luke 1:31 NIV). Do you see the two independent clauses? The first, “You will be with child and give birth to a son,” could stand as a sentence by itself. The second, “you are to give him the name Jesus,” could also stand alone as a sentence. What joins them is a comma, followed by one of the FANBOYS conjunctions—and.
- Use a comma to set off introductory elements and direct address. The word “introductory” is a clue: it refers to a word or short phrase at the beginning of a sentence, before the subject and verb—that is, before a clause that can stand alone as a complete sentence. “When I study grammar, my blood boils.” “When I study grammar” is the introductory phrase—it can’t stand alone as a complete sentence. It is a dependent clause—that is, it is dependent on something else to complete the thought so the reader isn’t left hanging, which would not be good. “My blood” is the subject and “boils” is the verb, and taken together the three words can stand alone as a complete sentence. It finishes the thought begun by “When I study grammar.” Sometimes, an introductory element is just one word and is set off from the rest of the sentence by a comma (like sometimes at the beginning of this sentence). Not all grammar authorities agree that a comma placed after a single introductory word is necessary if the meaning is clear without it. Use your own judgment, but be consistent.
We also use a comma in direct address: “Dean, it’s time to move on.” Conversely, if we flip that around, we still need the comma: “It’s time to move on, Dean.” While we’re on the topic of direct address, let’s join the growing national movement to restore the missing comma in our greetings, thank-yous, and well wishes. Note the comma placement in these examples: “Happy birthday, Harpo!” “Congratulations, Zeppo!” Thank you, Gummo!” “Howdy-doody, Bozo!” I know that cell-phone texting habits have all but killed that comma, but we must resist and stand firm! Let us make our world a better place for our grandchildren.
- Use a comma to set off interrupters and appositives. Interrupters are nonessential words or phrases that interrupt the thought of a sentence but are not essential to the meaning of the sentence. You surround the interrupter with commas—one before and one after. You can use parentheses or dashes to do the same thing, if you so choose, but here we’re talking about commas. Okay, stop and look at the previous sentence. See the interrupter? The phrase “if you so choose” is not essential to the meaning of the sentence. Mentally take it out and reread the sentence. That’s the test of whether you will need to set off a phrase with a pair of commas.
Similarly, when you follow a noun with a word or phrase in order to describe or give more information about it—something called an appositive—you need commas: “Duck Soup, the Marx Brothers 1933 classic, is on the American Film Institute’s list of top 100 all-time films. The phrase “the Marx Brothers 1933 classic” is additional information about the previous noun, “Duck Soup,” and needs to be set off with commas. It’s an appositive phrase.
An appositive can go at the end of a sentence as well: “One of AFI’s all-time top 100 films is Duck Soup, the Marx Brothers 1933 classic.” Note the comma after Soup. It indicates that what follows is an appositive phrase—I’m positive! The information is nice to have and maybe even important, but not essential to understanding the sentence. If a word or phrase is essential to the meaning, don’t set it off with commas. “One of AFI’s top 100 films is the Marx Brothers 1933 classic Duck Soup.” If that’s the way you choose to write the sentence, then every word is essential to its proper understanding. No commas are needed.
- Use a comma to separate a direct quotation from its attribution (i.e., who said it). Here’s an example: “‘That’s pretty straightforward,” said the semi-comatose blog reader.” Notice the comma? We can also flip it around: “The semi-comatose blog reader said, ‘That’s pretty straightforward.’” Here’s one catch: if it’s an indirect quotation, no quotation marks or comma are required. The almost-sleeping blog reader said that it was a very simple. See? No quotation marks and no commas. Piece of cake! Here’s a tip for students writing papers so you don’t get nailed for plagiarism: If you make a direct, word-for-word quotation (as in the first example), give the source appropriate credit. That’s called a citation. If you make an indirect quotation, as in the second example, you will still need to give a source citation, even though you changed the words a little. Why’s that? Them’s just the rules. (Yes, I know that’s not proper grammar.)
- Use a comma to separate two or more coordinate adjectives describing the same noun. Now I know you’re ready to run for the hills. But wait! It’s not so bad with an example or two. “For my birthday I want a tall, round, calorie-free, chocolate cake.” The noun here (chocolate cake) is described with various adjectives. A simple test will help you decide if and where you need to place commas: the “and test.” If you can replace the commas with the word and, and it makes sense, the commas are good. Let’s try it: “For my birthday I want a round and tall and calorie-free chocolate cake.” Yep, that makes sense. Another test is to mix up the order of the adjectives: “For my birthday I want a calorie-free, tall, round chocolate cake.” Yep! Still good. Let us eat cake!
- Use commas to set off dates, place names, titles, and addresses.
- Dates, when used in a sentence: “On July 4, 1776, Nettie Shoemaker walked her dog downtown.” See the comma after 1776? Strangely, that’s how it’s done.
- Place names: “Nettie lived in Philadelphia, Pennsylvania, during the American Revolution. Notice the comma after the state name? Yes, it’s supposed to be there.
- Titles: “Dr. Nettie Shoemaker, M.D., was inspired to open her own medical practice after watching Quinn, Medicine Woman on television. M.D. is set off with commas. (And here’s a freebie: Medicine Woman is an appositive describing Dr. Quinn, so there must be a comma after Quinn.)
- Addresses: Shoemaker lived at 7 Main Street, Philadelphia, Pennsylvania. Simple, right?
- Use commas to indicate interdependent clauses and antithetical elements.
- Interdependent elements. Okay, don’t throw up your hands—this isn’t as difficult as it seems. Here are examples of interdependent elements: “The longer the article, the sleepier I get.” “The bigger they are, the harder they fall.” If it’s a very short sentence, no comma is needed: “The fewer the better.”
- Antithetical (or contrasting) elements are set off with a pair of commas: “It’s the quality, not the quantity, that counts.” “We’re at the end, not the beginning, of this blog article.”
A caveat: the trend in American writing is fewer, not more, commas. Use them judiciously, but follow these guidelines. Doing so will help make your writing more clear, coherent, consistent, and yes, correct.
 Amy Einsohn, The Copyeditor’s Handbook (Berkeley: University of California Press, 2011), 95.
© 2018 by Dean Christensen