Punctuation particulars: the long dash

Copy editors can be picky. We like accuracy, clarity and consistency. We like to have a good reason for stepping outside the bounds. A recent message from a colleague that referred to the dash as "trite punctuational hyperbole" seemed harsh and rigid to other colleagues. In fact, when I was first hired at The N&O in 1987, we were told to use dashes sparingly. That seems to have changed in the past 10 years or so. Now, our copy can be sprinkled with dashes.

I decided to do some research on the use of the dash, also known as the em dash ("em" is a printing term that refers to width) or the long dash. I wanted to know the rules of using dashes.

(In this post I am not considering the en dash, which our newspaper rarely uses. I will use two hyphens side by side to represent an em dash in this post.)

First, Strunk & White, as one colleague noted, has this to say about the dash:

"Use a dash to set off an abrupt break or interruption, and to announce a long appositive of summary. A dash is a mark of separation stronger than a colon, and more relaxed than parentheses. Use a dash only when a more common mark of punctuation seems inadequate."

The Capital Community College's Guide to Grammar and Writing site opens a page on dashes with a wonderful quote from the writer-scientist Lewis Thomas:

"The dash is a handy device, informal and essentially playful, telling you that you're about to take off on a different tack but still in some way connected with the present course -- only you have to remember that the dash is there, and either put a second dash at the end of the notion to let the reader know that he's back on course, or else end the sentence, as here, with a period."

The Guide to Grammar and Writing refers to the dash as a "super-comma" and tells students to forgo the dash when a comma will do. That's good advice, but it's subjective. Maybe I think commas will do, but another writer thinks that the break is not strong enough without the dashes.

Dashes do put more emphasis on the words that have been set off. Merriam-Webster's Guide to Punctuation and Style, Second Edition, says that a dash "marks an abrupt change or break in the structure of a sentence." An example: Almost all of us wanted to visit the museum -- Susan wanted to go shopping. I prefer a semicolon in that spot, but someone else could argue that the sentence needs the tension of a long dash -- to indicate exasperation, perhaps.

Dashes often appear these days to link two clauses. I am old-fashioned; I think semicolons (or a comma and a coordinating conjunction) work best to link two independent clauses.

Sometimes, a set of long dashes acts as commas and parentheses would: to insert explanatory or amplifying phrases. Example: We went to the mountains -- mostly Blowing Rock or Boone -- for weekend outings when I was a child. Commas would do in this case, but a writer might choose dashes for emphasis. Another example: We went to the mountains -- I was a reluctant passenger in the backseat -- almost every weekend during the summer. Parentheses would work here. Some writers might consider parentheses too jarring; they want to keep the flow going even while emphasizing the aside. 

The Merriam-Webster's punctuation guide also says that a dash can introduce a summary statement after a list. Jobs, health care, infrastructure rebuilding, security -- those are some of the concerns on voters' minds.

A dash can set off a definition. The bank used credit default swaps -- a complex form of insurance that pays if a borrower defaults -- to make its mortgage holdings appear stronger than they were.

I think writers should acquaint themselves with all available punctuation tools. The Associated Press Stylebook has a punctuation guide that mass media writers can refer to. Writers and editors can choose to use the ones that work best. Many writers seem to have forgotten the semicolon, for example, and use dashes to excess. But no tool should be off-limits -- unless your teacher or editor deems them so.