Are You Coordinating?

I think one of the more subtle problems in punctuation is understanding a coordinate adjective and when to use a comma. It’s up to you to determine if the adjectives describing a noun are coordinate or “equal” in their description. If so, you need a comma. A trick to figuring out if you need a comma is to say the sentence a different way. Here’s what I do:

First, the sentence: I have a thick wide green book.

I then say, “I have a book that is green, wide, and thick.” Wide and thick are similar adjectives, but green describes the book in a different manner. In fact, I have a green book that is thick and wide. That means I would punctuate the sentence like this:

“I have a thick, wide green book.” You don’t want to separate the noun from the immediate adjective with a comma.

Wrong:

A big, house
An angry, African lion.
A tall wide building [tall and wide are similar types of adjectives so you need the comma]

There are two “tests” to see if a pair of adjectives is coordinate: Use a comma if you can place and between them and if you can reverse the order.

Example:

I have a horrible, pounding headache.
I have a horrible and pounding headache.
I have a pounding and horrible headache.

To me, this sounds funny, so I would not use a comma:

I have a horrible pounding headache.

But this sounds right:

He raced a sleek, shiny boat.
He raced a sleek and shiny boat.
He raced a shiny and sleek boat.

Sometimes it’s not quite clear if adjectives are coordinate, but if you restructure the sentence a few different ways, you should be able to tell. I like the example discussed in The Copy Editor’s Handbook (Amy Einsohn): A battered old canvas fishing hat. Because none of the adjectives is coordinate, you don’t need a comma anywhere. Can you tell?