When I first posted on this blog, I mentioned that I also wanted to use this space to foster a discussion about grammar, punctuation, and many other issues surrounding language usage. For a while, I hemmed and hawed about how to start, and figured that one of the things I gave a lot of though to (and had a lot of internal debate about) was the serial comma.

Then I got a mass mailing from the EAC asking members to vote about their opinions on the serial comma, which would then be published in the next volume of their publication Active Voice. Since I had been mulling over posting about it, this just sealed the deal. So: a discussion of the serial comma it is!

To those who don’t know, the serial comma (also known as the Oxford comma, don’t ask me why) is the comma placed before “and” or “or” in a series of listed items. I’ve made use  of it at the end of the first sentence in this post: “I also wanted to use this space to foster a discussion about grammar, punctuation, and many other issues surrounding language usage.” As a comma-happy writer, I used to think that the serial comma was unncessary – that the use of “and” or “or” in the phrase in question indicated clearly enough the proper speaking rhythm. There are many people who continue to feel the same way.

However, I have come to the realization that when I write, or when I read what is written by others, that even the slightest ambiguity in cadence or rhythm disturbs me. As well, the copy editor’s job is to review text and make sure that any grammatical or syntactical ambiguities are removed in the text in question, and many times adding a serial comma makes sentences clearer, especially when the items in a list consist of conjunctions, are long, are participial phrases, or when parallelism needs to be reinforced. Here are some examples:

• Otis’ favourite chores are grouting the bathtub, sweeping and cleaning the litter box, and dusting the bookcases. Here, the serial comma is imperative, or else the end of the sentence would read “sweeping and cleaning the litter box and dusting the bookcases” – which just makes you sound like you’re five years old. We want readers to understand “sweeping and cleaning the litter box” as a single discrete chore.
• Adding a serial comma makes sentences clearer, especially when the items in a list consist of conjunctions, are long, are participial phrases, or when parallelism needs to be reinforced. A trick I often use to understand long lists and to see whether their grammatical constructions are sound is to remove items from a list and see if the resulting sentence scans properly: “Adding a serial comma makes sentences clearer, especially when the items are long” or “especially when parallelism needs to be reinforced.” Because “consist of conjunctions,” “are long,” “are participial phrases,” and “when parallelism needs to be reinforced” all have multiple words, adding the serial comma here reinforces that all items in this list individually make sense when preceded by the word “when.”

Here’s an example of where I don’t think the serial comma is necessary:

• I would like to give my thanks to Bob, Lorraine, Delia, Cory and Otis. Here, the items being listed are so short and unambiguous that the serial comma just adds clutter.

So, to sum up: serial commas aren’t always necessary, but they often make for easier reading. It is best to use them when the items being listed are long phrases, or when not doing so would invite ambiguity.

Edit (November 30 2009): Of course, in the interest of consistency, once you are copy editing a document, decide whether or not you wish to use the serial comma and STICK WITH YOUR CHOICE. Put it on your style sheet. This is one of the biggest reasons why I’m pro-serial comma: because there are so many more instances where I think it’s needed than where it isnt, it’s easiest to just use it and be consistent.