Columns > Published on April 19th, 2012

Three Comma Rules You Need to Learn Now! NO MORE EXCUSES!

Something terrible has happened; teachers are actually instructing their students to drop the comma before the word and in sentences that use serial (or list) commas. I learned this today while talking to a coworker about some corrections he made to document. When I asked him why, he said his college professor had told him never to put a comma there, and she actually graded him down for doing so.

Sensing this was “a teachable moment,” I walked back to my desk to get my Chicago Manual of Style and The Little, Brown Compact Handbook to show this misled chap the right way. The worst part of it all is that, unlike so many of my victims, eh em, students, this guy cared to get it right. He had truly learned what his professor told him and acted on this knowledge without question. It got me thinking, how many others out there have been confused in this way?

Though most of my own teachers and professors had advocated the comma before and, I’d had a couple teachers who told me that sometimes the comma was not necessary, but no one ever bothered to clarify. Teachers only said to pick one and be consistent, and I can’t remember any who graded me down for using one or the other.  Now, this seems like such a cop-out, and I wished they’d been more clear. Then there was this crazy prof my coworker had… my goodness, what was her problem? Never use a comma? Someone must have pissed her off once about this whole comma thing, and now she was taking it out on whole classrooms full of malleable minds. Inexcusable.

This seems like a perfect opportunity to make a stand and nail down at least three comma rules once and for all. Since I made such a stink about it, let’s start with this rule:

Use a comma between items in a series or list. 

The Chicago Manual of Style, 15th ed., states that “items in a series are normally separated by commas. When a conjunction joins the last two elements in a series, 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.” As you may or may not remember, conjunctions “hook up” words and phrases. The most common conjunctions can be remembered with the acronym FANBOYS.

For, And, Nor, But, Or, Yet, So

In most sentences requiring a serial comma, you’ll see and, or, and nor used most often.

The Little, Brown Compact Handbook, 5th ed., states that a comma must be used between “three or more items of equal importance. These items may be words, phrases, or clauses.” The book does not specify about conjunctions, but it does mention that some writers might omit the final comma. However, it does not explain why or in what cases the comma can be omitted. This definitely leads to uncertainty.

Here’s a classic example of how this comma is used:

Taylor went to the store to buy apples, bananas, and oranges.

Here, the comma before the and is in place, and the message is quite clear. There are, however, other ways to write this sentence. Consider:

Taylor went to store to buy apples, bananas, oranges.

This is not wrong, just awkward, as is the comma-free alternative:

Taylor went to the store to buy apples and bananas and oranges.

In this version, the word and stands in for the commas, and the reader can be pretty clear about what Taylor bought at the store.

Admittedly, by that logic, and could also stand in for the last comma, and you wouldn’t be wrong.

Taylor went to the store to buy apples, bananas and oranges.

This is why there is confusion. In such a simple example as this, omitting the final comma makes sense as there can be little confusion about what Taylor bought. But, in other cases, omitting the final comma can create confusion.  This is, I am guessing, where people like my coworker's comma-angry professor went wrong. In both definitions, the rule does not clarify why the comma is recommended nor why some people just don’t use it.

Fortunately for us, we have Grammar Girl. I adapted the following examples from her book Grammar Girl’s Quick and Dirty Tips for Better Writing to explain why, despite these two books’ rather lame explanations, using a comma before the conjunction in a series makes sense most of the time.

For example, if I were a baker, I might make several different kinds of pies.

Taylor’s specialty pies are apple, strawberry and rhubarb, and peach.

Note that this sentence refers to three different pie flavors:

  • apple pie
  • strawberry and rhubarb pie
  • peach pie

Assume, then, I have my coworker's comma-angry professor, and she made me omit the final comma before the “and”. Observe:

Taylor’s specialty pies are apple, strawberry and rhubarb and peach.

Without the comma, the reader would assume I only have two specialty pies to offer:

  • apple pie
  • strawberry and rhubarb and peach pie

While delicious either way, it’s definitely confusing. In this particular case, I would want to be clear about the number and flavors of pies I’m selling, therefore, I’d use the comma before and.

Here’s one more way to word it:

Taylor’s specialty pies are apple, peach, and strawberry and rhubarb.

In this case, I would definitely leave out the comma before the final and because I still want to convey that I only make three different kinds of pies. Furthermore, as you can see, I have put a comma before the first and to make this very clear.

Consider another example of where an omitted comma can cause a lot of confusion. Grammar Girl uses the example of a court case in which damages are awarded to three people.

One million dollars will be awarded to Taylor, Josh and Dennis.

Now, assuming we follow the logic of the fruit example above, and we assume that the word and is a perfectly good substitute for the final comma, then we can believe that the one million dollars is being split three ways. However, maybe I’m a total bi-atch, and I surmise that, actually, I am getting half a million dollars, while Josh and Dennis are splitting the other half, thus making the split 50/25/25 instead of 33.3/33.3/33.3. Without that final comma, I could very well argue that Josh and Dennis are a single party, while I am the other party, and I could end up a lot richer than either of them.

Thus you can see that while “some people” may omit the final comma, the wise writer will use it 99% of the time because it just makes good sense. This is why most reputable style manuals recommend it and why you are generally safer using it than not.

Use a comma between two independent clauses separated by a conjunction.

This rule is less controversial, but I still see writers of all levels miss this one frequently. As you will remember from the previous section, the common conjunctions are:

For, And, Nor, But, Or, Yet, So (FANBOYS)

Clauses are sections of a sentence, and, as intimated by its name, an independent clause is a section of a sentence that could stand independently as a sentence all its own. And, for a sentence to stand on its own, it must contain a subject and a verb, i.e. be a complete thought. The idea here is that when two complete thoughts, or sentences, are connected with a conjunction, they form a compound sentence delineated by a comma. Of course, in order for it to make sense to connect the two sentences in the first place, they ought to be related in content, tone, and idea. This may seem like a bunch of grammatical jargon at this point, but chances are you know this rule intuitively already. Here’s an example to refresh your memory.

Taylor won the law suit against Josh and Dennis.  She is a very wealthy woman.

Of course these two sentences are just fine as they are, but they read like two random facts: Taylor won the suit. Taylor is wealthy. However, we want the reader to know that though true independently, the facts are related. Therefore, we would recraft these sentences into a single sentence using a comma and a conjunction.

Taylor won the law suit against Josh and Dennis, so she is a very wealthy woman.

Note that each sentence has now become an independent clause connected with the comma/conjunction double-team. Each clause has a subject (Taylor/she) and a verb (won/is). But, because Taylor is actually subject of both verbs (she=Taylor), this could be condensed into a single sentence with no comma or conjunction. Observe:

Taylor won the lawsuit against Josh and Dennis so is a very wealthy woman.

Since Taylor is the subject for both verbs (won/is), the second part of the sentence is actually a dependent clause, as it depends on the subject of the first part of the sentence. Therefore, it should not be separated by a comma. The conjunction, however, stays because it indicates the relationship between the two sections of the sentences.

Now, The Chicago Manual of Style states that a comma may be omitted before the conjunction even if there are two subjects and two verbs when the following condition is met: the second subject/verb combo is very short and closely related to the context of the first part of the sentence. For instance:

Josh thought Taylor was a conniving gold digger and Dennis agreed.

If we pull these two clauses apart to make sure they can stand on their own as sentences, we’d see that, yes, they could:

Josh thought Taylor was a conniving gold digger. Dennis agreed.

The second sentence is very short and consists of the bare minimum subject (Dennis) and verb (agreed). While Chicago thinks it’s ok to omit the comma in such a situation, I would argue that consistency is always better. Like all style guides, Chicago is written for a specific audience—in Chicago’s case, it’s newspaper, magazine, and book editors for whom page space is at a premium. To them, it might be important to eliminate the space that a comma takes up in order to fit more content on a page. In my opinion, this is a pretty weak reason to ignore a very simple rule. For the average writer, I’d suggest using the comma/conjunction combo whenever you need to link two complete ideas this way. Most of us are not trying to save such tiny increments of space. In my opinion, clear, consistent writing always wins over nitpicky exceptions that won’t be clear to every reader.

If you are, for some reason, desperate to save space, a semicolon can also do the job of a comma/conjunction combo.

Josh thought Taylor was a conniving gold digger; Dennis agreed.

By using the semicolon, you are showing the relationship between the two ideas by combining them into a single sentence, but avoiding addition of the comma and and. This has a slightly different effect because it backs the two ideas up to each other to show relationship but without showing exactly what that relationship is. It’s also a little more jolting to read, as the comma/and combo smoothes it out. It can work, and it is a style choice on your part. Both ways are correct.

Use a comma between two adjectives preceding a noun.

This particular error is rampant. When editing, I almost always run across adjective pairs that lack a comma to separate them. It irks me. But then, I’m like that. This is a VERY simple rule that no one should get wrong, so let’s learn it once and for all, shall we?

According to The Chicago Manual of Style (15th ed.), “when a noun is preceded by two or more adjectives that could, without affecting the meaning, be joined by and, the adjectives are normally separated by a comma.” For example:

Dennis told everyone that Taylor was a devious, greedy thief.

Per Chicago’s rule, this sentence could also be written with and instead of the comma:

Dennis told everyone that Taylor was a devious and greedy thief.

In both cases, the adjectives (devious and greedy) are modifying the noun (thief).

The only exception to this rule that I can find is when the second adjective is basically a part of the noun. For instance “young boy” and “religious association” are taken as single units. In these cases, the adjective is really part of the noun. If this is the case, you can omit the comma. For example:

That is a smart young boy.

The Catholic Church is a large religious association.

These are not very common, and if you have to think hard about whether or not a certain adjective/noun pairing is a unit, then it’s probably not, and you are safer using a comma.

One other scenario to watch out for is adverbs. Adjectives modify nouns while adverbs modify verbs. (Ad-VERB, get it?) Depending on their position in the sentence and the context, words that end in –ly may serve either as adjectives or adverbs. Grammar Girl’s Quick Dirty Tips for Better Writing gives the example of the word daily. This word can be used as an adjective to modify a noun such as the word commute in the following example:

Taylor’s long, daily commute gives her plenty of time to think about writing.

Or it can be used as an adverb for the verb to commute in this example:

Taylor commutes far daily.

Note that in the first sentence, the two adjectives are separated by a comma because they both modify the noun commute. In the second sentence, far is an adjective, but daily is now an adverb that is modifying the verb commutes, so there is no comma used.

Your Mission

While it may seem tempting to throw our hands up and say that since there is possibility for confusion and special circumstances, there’s no reason to follow these rules. That is not the case. In fact, if the rules are followed consistently, then the special circumstances are just that—special and rare. I can’t imagine what happened to my coworker’s professor to make her eschew all serial commas once and for all, but I think what she did was wrong. She did not do her research and, as a result, she has confounded whole rooms full of students. As writers and lovers of language, we should stand up for the rules. Learn them. Use them. Teach them. Of course they shift and flex, but that is the wonderful thing about language. I firmly believe that you must learn the rules before you break them, so learn these three comma rules—NOW!

You assignment this week (and forever) is to look up these rules yourself. To write this article, I used three different books, but there are SO many, and other books may cite other exceptions or examples. Or, they may simply state the rule and call it good. Either way, learn these three comma rules to the point that you feel confident in your knowledge. Practice using them in all of your writing—emails, poems, manuscripts, tweets. Then teach them to another person. Or, if these are something you know well already, tell us all about it. How did you learn them? What did it take to make it stick? Have you ever taught them to someone else? How did that go? Please share your experience in the comments section below. 

Photo by Steve Kass

About the author

Taylor Houston is a genuine Word Nerd living in Portland, OR where she works as a technical writer for an engineering firm and volunteers on the planning committee for Wordstock, a local organization dedicated to writing education.

She holds a degree in Creative Writing and Spanish from Hamilton College in Clinton, NY. In the English graduate program at Penn State, she taught college composition courses and hosted a poetry club for a group of high school writers.

While living in Seattle, Taylor started and taught a free writing class called Writer’s Cramp (see the website). She has also taught middle school Language Arts & Spanish, tutored college students, and mentored at several Seattle writing establishments such as Richard Hugo House. She’s presented on panels at Associated Writing Programs Conference and the Pennsylvania College English Conference and led writing groups in New York, Pennsylvania, and Colorado for writers of all ages & abilities. She loves to read, write, teach & debate the Oxford Comma with anyone who will stand still long enough.

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