Which one is correct:
short answer question
or
short-answer question
If both of them are correct how do they differ from each other?
Which one is correct:
short answer question
or
short-answer question
If both of them are correct how do they differ from each other?
Short-answer question would be more correct in any plausible situation.
Having the dash just directly correlates the fact that what you're looking for is a "short answer" to your question, without having to write it out as I have.
On a technical level, neither are incorrect but readability is greater in the latter option.