Using Dashes
Dashes are used to emphasize some inserted text. (In contrast, putting words in parentheses like this de-emphasizes the inserted text.)
Dashes should be used sparingly in academic writing. Prefer the more common punctuation marks, such as commas and colons, when possible.
Format Note: To type a dash (—) on most computers, type two hyphens (- -) with no space before, between or after the hyphens. Some word processors automatically turn two hyphens into a dash.
Examples:
The survey found that few community members were familiar with the entire range of our services—just what we had feared.
The consumer's problems—lack of education, little family support, no employment record—were offset by his strong motivation to succeed this time.