Proper Punctuation and Grammar

Punctuation: Colons Vs Dashes Vs Parentheses

Punctuation can determine the interpretation of a contract, fix the price of your product, or alter the tone of your email. Never underestimate its importance.

If you’ve ever tried to drive in Manila, Philippines, you know that traffic signals can be your friend, not your enemy. You leave your hotel for a venue 2 or 3 miles away, and it may take you 2 hours to get there because traffic signals (where they exist) carry little authority.

A common joke on the streets: “How do you identify newcomers to The Philippines?” Answer: “They wait for an opening before pulling into the traffic.”

In the opening three paragraphs, I’ve used several marks that serve as reading aids—marks that lead you along the way. Without those marks (colons, parentheses, quotation marks, dashes), it would have taken you much longer to read and understand the passage.

Punctuation marks have meanings in the same way as math symbols do: 2 X 2 = 4.

Three related punctuation marks that seem to confuse business writers often are the colon, the dash, and the parenthesis—particularly, when those three might be used interchangeably.

Examples (all correct):

Our consulting services can help with maintenance after installation:  modeling, cradling, painting.

Our consulting services—modeling, cradling, painting—can help with maintenance after installation.

Our consulting services (modeling, cradling, painting) can help with maintenance after installation.


See the three rules that follow to understand the different emphasis in the above three examples.

How Colons, Dashes, and Parentheses Differ

  • Colons highlight what follows them. (Example 1 above)
  • Dashes highlight what’s between them. (Example 2 above)
  • Parentheses downplay what’s inside them. (Example 3 above)

Colons Highlight What Follows

Gary supervises four people: Tom, Depak, Marita, Kimberly.

The executive’s attitude toward the partnership was unexpected: arrogant, belligerent, illogical.

Dashes Highlight What’s Between Them

Gary supervises four people––Tom, Depak, Marita, Kimberly––and each of them have made the President’s Top 1 Percent Club every year since they joined the organization.

The executive’s attitude toward the partnership—totally shocking and unexpected—was arrogant, belligerent, and illogical.

Parentheses Downplay What’s Inside Them

Gary supervises four people (Tom, Depak, Marita, Kimberly) and cannot easily schedule a vacation at the end of the year.

The executive’s attitude toward the partnership (arrogant, belligerent, and illogical) was totally unexpected to most of us in the room.

Of course, there are a few other uses for the colon, the dash, and a set of parentheses. But the preceding usage is what confuses most writers because the marks can be interchangeable. The use depends on your intended meaning.

At this point, you may want to circle back to the opening paragraphs and reread, noticing how the parentheses, colons, and dashes convey voice inflection and meaning.

Precise punctuation provides the traffic signal that makes reading—and communication—quick and easy.

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