Q: When writing a sentence that contains a series of something (e.g., a butcher, a baker, and a candlestick maker), do I need a comma before the "and" connecting the final two elements? I've seen it with and without. Please help. —Anonymous
A: The reason you've seen it both ways is quite simple: Both ways are acceptable. It's not a grammar rule; it's a style choice. It's kind of like wearing white after Labor Day—some say it's fine, some say it's a reason to call the fashion police, but ultimately there is no right or wrong and you get to pick which group fits you. But, as with wearing white in October, there are factors to consider before making your choice.
Most modern writing guidebooks like Garner's Modern American Usage and The Chicago Manual of Style say you should always use the serial comma before "and." The reasoning behind this is to avoid ambiguity and confusion. For example, The teacher divided the teams into Jennie and Carson, Mark and Tom, Chris and Ella and Anna and Mia. The way this sentence is laid out without a serial comma, you could make the argument that there are four teams of two. You could also argue that there are two teams of two and one team of four. Adding in the serial comma (The teach divided the teams into Jennie and Carson, Mark and Tom, Chris and Ella, and Anna and Mia) helps clarify the sentence for readers.
The anti-serial comma group mainly consists of newspaper and magazine editors (and Writer's Digest editors) who 1) adhere to the Associated Press Stylebook rules of omitting the serial comma and 2) leave it off because it saves space (print publications have such a finite space to work with that if we can cut anything, we do). Often, editors and other literati argue that it's unnecessary and should be added only when needed to clarify meaning. These are the folks who wear white after Labor Day.
Until I joined the WD staff, I always used the serial comma and was an ardent supporter. But after years of getting "corrected" by strong-willed managing editors, I finally acquiesced and ditched it for good. Sometimes I feel guilty, like I've abandoned an old friend (though he does sneak his way in occasionally, for old-time's sake). But the truth is, I don't feel my writing has suffered any from writing without it. And when you can simplify your writing without changing the meaning, you should. That's why I packed away the serial commas for good. Of course, I now also wear white year-round.
EDITOR'S NOTE: A couple of lawyers mentioned that the serial comma is necessary in legal documents and, without it, the courts will read it differently (thus misinterpreting the meaning). So in all legal documents, include the serial comma.