I've been teaching a lot lately to business professionals, doing writing refresher courses, mostly helping them hone their skills. Each group has included a discussion of the hyphens and dashes and I thought I include that conversation here.
There are three pieces of horizontal punctuation. The hyphen, the briefest of the lines, joins words together and is often used between numbers to indicate a range (of years, pages, dollar amounts). The en dash, so-called because it is the width of the en in the font you are using, is a little longer than the hyphen and has a conservative use limited to the negative sign in math or science.(More liberally, it is used in place of the em dash.) The em dash, again the width of the em in the font you are using, is the longest of the three lines and is used in place of commas, either to create an informal look or tone or to create a more dramatic visual effect on the page. En dashes are typically formatted with spaces before and after; the em dash calls for no space before or after.
Hyphenating compounds that are forming adjectives was the topic of our conversation during the recent courses. I'm a strong proponent of reader-focused writing and using the hyphen correctly helps speed comprehension for all readers. A good example of this use of the hyphen occurs in the preceding sentence: reader-focused writing. The two words "reader" and "focused" are not used individually to describe writing; rather, they are used as a combination, as a unit of meaning. When this unit precedes the noun it describes, it should be hyphenated for clarity. Here are some common examples:
a long-term issue
an agreed-upon condition
a money-based conversation
a cancer-related treatment
a part-time worker
Note that when these words don't precede the noun, they are usually not hyphenated.
I'm in it for the long term.
We agreed upon the condition.
The conversation was based on money.
However: He works part-time. His treatment was cancer-related.
Here's my favorite example.
He's a short distance runner.
He's a short-distance runner.
Both sentences are correct. The meaning differs. Email me if you don't see how (sobertruths@gmailcom) and I'll tell you.