Dashes

There are three types: hyphen (-), en-dash (–), and em-dash (—).

Most compounds formed with prefixes are unhyphenated:

Predetermined
Nonobjective

Except when used with numbers, proper nouns, open compounds (non-self-sustaining), or when misreading could occur (pro-life):

Pre-1970
Non-self-sustaining
Sub-Saharan
Pro-life

Except for “coordinate and “cooperate,” use a hyphen when the same vowel ends the prefix and begins the word that follows:

Anti-intellectual
Semi-independent

Hyphens

Many common questions concern hyphenation. Should compound terms such as “aftermath” and “countermeasure” be written as one word, two words, or hyphenated? Prefixes and suffixes can be troublesome also.

The choice is based on usage, so the first place to look for answers is the dictionary. A guiding principle is clarity. If hyphenation makes the meaning of a word or phrase more clear, it may be best to use it.

The rules below are well accepted, and you can safely use them as a guide:

Use a hyphen with the prefix “co” when forming nouns, adjectives, and verbs that indicate occupation or status:

co-author, co-sponsor, co-worker, etc.

When in doubt, check Merriam-Webster’s Collegiate Dictionary.

Use hyphens for compound words. For example, a compound adjective that precedes the noun it modifies and word division. These should be closed up—no space before and after—to surrounding text:

Snow will only be cleared from high-traffic areas.
The study found that satisfying part-time work is hard to find.
Starting in January, she will be in the position full time.

En-dashes are used with number ranges and to indicate “to” or “through.” They should be closed up—no space before and after—to surrounding text. (PC shortcut is ctrl + keypad hyphen; Mac is option + hyphen). En-dashes are reserved for calendar entries, sidebars, charts, and the like. An exception in running text is the expression of academic years (i.e., 2008–09):

More students participated in Foreign Study Programs in 2008–09 than in previous years.
The light display will run December 1–30.

Em-dashes are used to set off an explanatory element within a sentence. Commas and parentheses perform a similar function. They should be closed up—no space before and after—to surrounding text for print media. Spaces are inserted for web media. See The Internet section for additional details. (PC shortcut is alt + ctrl + keypad hyphen; Mac is shift + option + hyphen):

Three important elements—cost, effectiveness, and availability—will be considered.

Semicolons

Use to separate items in a series when one or more of the items contain a comma;

Important points to consider are privacy; social, cultural, and economic factors; and status.

Quotations/Quotation Marks/Speech Verbs

Set speech verbs in the past tense:

“There is no doubt that energy, sustainability, and climate change will be the defining challenges of this century,” President Gutmann said.

When continuing paragraphs of a quote on multiple paragraph breaks, do not use ending quotes on intervening paragraphs.

“There is no doubt that energy, sustainability, and climate change will be the defining challenges of this century,” President Gutmann said.

“We owe it to future generations to leave this world as we found it, at the least. At best, leave it better than it was during the time we spent time on it.

“There is no higher responsibility for anyone who shares our common space.”

Commas and periods are always set inside of quotation marks. Colons and semicolons are always set outside of quotation marks. Exclamation or question marks fall inside of quotation marks only when they are part of quoted material. Commas should never be used in combination with exclamation or question marks.

Remember to use quotation marks (‘ ’, “ ”), and not tick marks (', "). Tick marks denote feet and inches.