The Comma

Writing converts the sounds and images we hear in our heads into symbols that are meaningful on a page. The comma enables us to add inflection normally reserved for oral communication to our writing.

Unfortunately, the comma is one of the most overused and misused punctuation marks in English. Frequently, writers use a comma whenever they sense a pause in their thought or speech, or to offset a section of text for aesthetic or thematic reasons. It is easy to use a comma whenever you are unsure of yourself. A manuscript riddled with commas is no different than a speech slowed down by mumbling and false starts: it implies a lack of confidence in what you have to say.

Use commas only when necessary. Tighten your prose to avoid the excessive use of commas.

Follow these guidelines when using commas:

• Use a comma to separate each item in a list of items, including the last two.
• Use a comma and a conjunction to connect two independent clauses.
• Use a comma on both sides of a parenthetical reference.
• Use a comma after adverb clauses and introductory phrases.
• Use a comma to offset contrasted phrases.

Use a comma to separate each item in a list of items, including the last two.

When you are listing items in a sentence, use a comma to separate each item from the other.

There is some debate about whether you truly need a comma preceding the word 'and' in a series; journalists often eschew the final comma for the sake of space. However, the comma clarifies the sentence, preventing readers from associating the final two elements with one another.

The difference is obvious:

The greatest influences on my writing were my parents, Ray Bradbury and Squeaky Fromme.

The greatest influences on my writing were my parents, Ray Bradbury, and Squeaky Fromme.

One simple comma prevents us from imagining the unholy union of Ray Bradbury and Squeaky Fromme. Use it when you need it.

The world runs on greed, money, and sex.

After Grandma died, we found a rifle, a barrel of corn whiskey, and a worn military jumpsuit in the trunk of her car.

Use a comma and a conjunction to connect two independent clauses.

An independent clause includes both a subject and a predicate and can function as a sentence of its own. When connecting two such clauses with a comma, use a conjunction to link the two. Otherwise, you are guilty of committing the dreaded comma splice:

• Incorrect: We climbed over the fence, the goats were already gone.
• Correct: We climbed over the fence, but the goats were already gone.

If you want to join two independent clauses but do not want to use a conjunction, use a semicolon:

We climbed over the fence; the goats were already gone.

If the clauses are short, you can avoid using a comma:

We were tired and we were disgusted.

You do not need a comma when joining a dependent clause:

Incorrect: We joined the military, and knew we were going to never see home again.

Correct: We joined the military and knew we were going to see home again.

You know a dependent clause from an independent clause because it cannot be used as its own sentence.

Use a comma to isolate parenthetical references.

Parenthetical references are phrases that add detail or color to a sentence but are not necessary to the structure. You can tell a parenthetical reference by removing it from the sentence. If the sentence is still structurally sound, the phrase is a parenthetical reference.

The world, ever oblivious to true greatness, would never know we'd saved it from destruction once again.

Harry, the obligatory town drunk, staggered to the microphone and demanded cheaper beer prices.

Use a comma after adverb clauses and introductory phrases.

An adverb clause is a clause that functions as an adverb, usually describing the action of a sentence.

We climbed Mount Hood, limping and complaining and weeping the whole way.

Slowly, he pulled his gun from the holster and set it down on the ground.

Use a comma to offset contrasted phrases.

Use commas in a sentence for dramatic contrast.

This company runs because of deception, not excellence.

Our children belong in school, not in mines testing for pockets of air.