As with the exclamation point, the problem here can be summed up in one sentence: People use it. Well, let me clarify just a bit.
When in Doubt, Dash?
People often use the dash when they are not sure what else to do. If you don't know if you should use a comma or a semi-colon at a certain juncture in your sentence, then I can almost guarantee you that a dash is not your best option.
One person actually told me that when she was in doubt about what punctuation mark to use in a sentence, she would just use the dash. Apparently she thought that the dash was a sort of "catch-all" that would always work. It doesn't. About 90% of the time when students use dashes in their term papers, it's wrong.
Not only is there a grammatical issue with the dash, but there are also mechanical issues with it as well.
# 1. Do not confuse the dash with a hyphen. The dash is twice as long as the hyphen.
The Difference between the Dash and Hyphen
There is a difference between the -- dash and the - hyphen.
The dash is an elongated hyphen called a "em dash" (thanks to David Peterson for correcting me) . See Turabian , 3.91 for more about this. Some typing keyboards have a dash, and others do not. When a keyboard does not have the dash, you can make a dash by typing in two hyphens (i.e., the "em dash."). This is what I must do for this web page; the em dash: "--"
One consistent error that people make with the dash is that they often put spaces before and after the dash. There should be no spaces.
Wrong --> The Bible is the best selling book of all time -- if you can call it just a book.
Right --> The Bible is the best selling book of all time--if you can call it just a book.
Use a dash to show dramatic contrast or emphasis.
Example: The Bible is the best selling book of all time--if you can call it just a book.
I was eating lunch--at precisely one o'clock--when the house caught on fire.
The over use of the dash is a sign of an inexperienced writer. You should use dashes very rarely.
The hyphen (not to be confused with the longer dash)
1. Use a hyphen between compound adjectives.
Adjectives are compound when both or several adjectives cannot stand independently with the noun.
Example: He gave her a diamond-studded ring. Max is a four-year-old dog.
Notice that Max is not a four dog. He is not a year dog. He is not an old dog. Thus, these adjectives must be hyphenated as four-year-old. Thus, Max is a four-year-old dog. However, when it is written like this, "The dog is four years old," there are no hyphens.
2. Use a hyphen between compound nouns. Example: They are bird-lovers.
3. Use a hyphen between adverbs and adjectives unless the adverb ends in "ly."
Example: It is a well-constructed house. It is a newly constructed house.
Don Ranly, Ph.D., professor of journalism, says that he allows his students to use the dash only twice in any term paper.
I have adopted this practice and limit my students to two uses of the dash per paper. And, even then, it must be used correctly.
For those of you who might be interested: I have produced a lecture series on audio with notes. I cover the basics of good writing, grammar, punctuation, and more. I've had people with Master's degrees and PhDs go through these lectures, and some of them told me that they learned more on this subject from my lectures and notes than they had from all of their previous education combined. You can listen to the lectures for free and downlaod the lecture notes as PDFa files (for free) at CES Writing Protocols Lectures.
Send comments about this, or any, Coffee Talk to Rick Walston at: CES - @ - ColumbiaSeminary.edu
(Please note that you will need to take out the spaces and hyphens before and after the @ sign . . . this is placed this way to avoid spam emails.)