If I called you a short story editor, would I be remarking on your height? I would be, if I didn’t hyphenate the phrase “short story editor.” To avoid misunderstanding, I would write “short-story” to make clear what the short is modifying.
The rule for hyphenating compound adjectives (things that describe nouns) is to leave them open unless the meaning might be misconstrued, such as in the example I gave.
Take a look at these:
- Free market economy (Is the market economy free, or are you talking about “free market” economy?)
- Secret police force (Is the police force a secret, or are you referring to the secret police?)
- Post office celebration (Is there a party at your local post office, or is this a party held after the office closes?)
You can see how hyphenating these compounds changes the meaning: free-market economy, secret-police force, and post-office celebration.
Common open compounds don’t need hyphenation:
- Mass transit route
- Baby boom generation
- High school student (unless you mean to show the student has been taking drugs—then you would need to clarify in some way)
So pay attention to these compound adjectives so you don’t accidentally say what you don’t mean.