Everyone seems to have their own rules about when to use and not to use a comma. Certain errors, however, keep popping up. The NYT presents a few of them:
Splice Girls, and Boys
“Comma splice” is a term used for the linking of two independent clauses — that is, grammatical units that contain a subject and a verb and could stand alone as sentences — with a comma. When I started teaching at the University of Delaware some years ago, I was positively gobsmacked by the multitude of comma splices that confronted me. They have not abated.
Here’s an example:
He used to be a moderate, now he’s a card-carrying Tea Partier.
It’s easy to fix in any number of ways:
He used to be a moderate. Now he’s a card-carrying Tea Partier.
He used to be a moderate; now he’s a card-carrying Tea Partier.
He used to be a moderate, but now he’s a card-carrying Tea Partier.
He used to be a moderate — now he’s a card-carrying Tea Partier.
How to choose among them? By reading aloud — always the best single piece of writing advice — and choosing the version that best suits the context, your style and your ear. I would go with the semicolon. How about you?
Two particular situations seem to bring out a lot of comma splices. The first is in quotations:
“The way they’ve been playing, the team will be lucky to survive the first round,” the coach said, “I’m just hoping someone gets a hot hand.”
The comma after “said” has to be replaced with a period.
The other issue is the word “however,” which more and more people seem to want to use as a conjunction, comparable to “but” or “yet.” So they will write something like:
The weather is great today, however it’s supposed to rain tomorrow.
That may be acceptable someday. Today, however, it’s a comma splice. Correct punctuation could be:
The weather is great today, but it’s supposed to rain tomorrow.
The weather is great today. However, it’s supposed to rain tomorrow.