Grammar Workshop: Do I need a Comma There? The problem of the Optional Comma

by Jennie Ruby

The rules of grammar are quite specific about some things. You say she is, not she are, for example. But when it comes to the comma, the rules of grammar break into three parts: commas that are required, commas that are forbidden, and commas that are optional.

One of the optional commas is the comma before and or or in a list of three or more items. This optional comma is so well known that it has a name: the serial comma. Other optional commas are less well known. We’ll take a look at one of those as well.

Use of the serial comma is one of the first style decisions you must make in a piece of writing. Journalistic styles generally do not use that comma; science and technical styles do.

Journalism:

• The conference today was attended by three candidates: Clinton, Obama and McCain.

Science/Technical:

• The diagram illustrates examples of atoms, molecules, and subatomic particles.

Once you have made your style decision about the serial comma, you use or omit it consistently throughout your document. The same is true for one of the other optional commas: the comma after an introductory phrase describing time or place. The grammar rule is that the comma is optional after a short phrase of time or place, but required for a longer phrase. It is a style decision whether the cut-off is one, two, three, or four words. If your phrase has five words or more, the comma is required.

Short phrases of time or place:

• In the morning I will walk the dog. (you could include a comma after the word morning)
• In 2007, we introduced a new product. (comma optional)
• After the severe tropical storm, the storm drains were flooded. (comma required)
• After all, the roads were never meant for so much traffic. (comma required–this phrase is a transition, not about time or place!)

When the comma is optional, you should still make a consistent decision about whether you are going to use that optional comma in a particular document or publication. A student in one of my classes mentioned that her office decided to use the comma after In [year], but not after other short phrases of time or place. By making a clear style decision to use-or not use-an optional comma throughout a document, you spare yourself the agony of making an individual choice on each sentence. And your readers will have a more consistent reading experience.

About the Author: Jennie Ruby is a veteran IconLogic trainer and author with titles such as "Essentials of Access 2000" and "Editing with MS Word 2003 and Adobe Acrobat 7" to her credit. Jennie specializes in electronic editing. At the American Psychological Association, she was manager of electronic publishing and manager of technical editing and journal production. Jennie has an M.A. from George Washington University and is a Certified Technical Trainer (Chauncey Group). She is a publishing professional with 20 years of experience in writing, editing and desktop publishing.

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