The em dash:

We’ve been seeing a lot of the em dash lately. Due to its versatility as a punctuation mark, it is now increasingly being used as a somewhat catch-all substitute for commas, colons and semicolons. Although this surge in popularity is not in itself a problem, it has at times resulted in the em dash being misused or overused, which in turn affects the clarity and structure of a piece of writing.

What is an em dash?

There are two main types of dashes, both of which are used in different ways:

The em dash or em rule (—), which is about the width of a capital M.
The en dash or en rule (–), which is about half the width of an em dash.

Correct uses of the em dash

This often depends on the style guide for the relevant publication, but generally according to the Style manual: for authors, editors and printers, 6th Edition, there are 3 main uses:

  • To indicate an abrupt change within a sentence

Livia is depicted within literary sources as holding political powers unusual for her time — but that is not the main focus of this piece.

  • To expand on or explain a point (replacing a colon or semicolon)

Livia is depicted within literary sources as holding political powers unusual for her time — she could receive the Senate, was given honours by the Senate and was able to influence the outcome of court cases.

Livia is depicted within literary sources as receiving the Senate, holding honours from the Senate and influencing the outcome of court cases — she thus displayed political powers unusual for her time.

  • To isolate parenthetic expressions

Livia — wife of Augustus — is depicted within literary sources as holding political powers unusual for her time.

Death of the semicolon and colon?

Maybe, but not necessarily. We generally limit our use of em dashes where:

  • too many em dashes may confuse the reader (for example, where there are more than two em dashes within a sentence);
  • more formal pieces of writing may require semicolons and colons instead.

And that’s the end of the story — or is it — you be the judge!