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The em dash: A valid punctuation mark – or artificial intelligence easy tell?

by Anna Jo Bratton, AP Stylebook editor on Aug. 27, 2025
In the AP Stylebook Online Ask the Editor feature, we often get questions about use of the em dash: when it’s appropriate, how to use it and whether it’s overused. It seems to live among types of punctuation that often come with strong opinions, like the Oxford comma.* 
But now, the question of the day seems to be:
If writing includes an em dash, does that mean it’s written by artificial intelligence? 
I’m not sure where this idea came from,
although I see it has been bubbling up online for some time. Popular podcaster Grammar Girl suggests it was a fashion podcast earlier this year that renewed the controversy, when it urged
people to stop using the “the ChatGPT hyphen.”  People are looking for authenticity and trying to pinpoint
any signs of something being inauthentic. It’d be nice if there was an easy
tell. 
Unfortunately, that tell is not the em dash, which has been around for many years. In fact, they
are so ubiquitous in AP lingo, we just call them dashes. They are about the width of a capital letter M, and always get a space on either side, except in sports agate. 
Some reasons to use an em dash, from the AP Stylebook: 
 
ABRUPT CHANGE: Use dashes to denote an abrupt change in thought in a sentence or
an emphatic pause: Through her long reign, the queen and her family have adapted —
usually skillfully — to the changing taste of the time. 
SERIES WITHIN A PHRASE: When a phrase that otherwise would be set off by commas contains a
series of words that must be separated by commas, use dashes to set off the
full phrase: He listed the qualities — intelligence, humor, conservatism, independence — that
he liked in an executive. 
 
We’re often asked if we have a limit on number
of em dashes per story. Some professors say they notice them
sprinkled to and fro like literary snowflakes, in student papers and
chancellor’s emails. 
AP does not have a limit on using long dashes.
But we agree that many writers overuse them. Our guidance says: "But avoid overuse of dashes to
set off phrases when commas would suffice. " 
Semicolons also work well. Or you could just
start a new sentence. 
If you’re really interested in dashes, did you know AP historically does not
use en dashes? Some other styles call for en dashes to indicate ranges, such as ranges of dates or times, or with some
compound modifiers. (An en dash is about half the
length of an em dash, approximating the width of a capital letter N). 
But at the AP, en dashes didn’t translate correctly to our newspaper
customers, who initially got “the wire” via teletype machines.  
I’m not sure if we’ll ever introduce en dashes back into the AP lexicon. Even if we do, don’t expect to see them popping up in a lot of AP stories right
away. Old habits die hard. 
 
Footnote: 
*For the last time (yeah, right), AP DOES NOT
ban use of the Oxford Comma. In fact, in some cases, we require it! Printed in our Stylebook are these words: “Include a final comma
in a simple series if omitting it could make the meaning unclear.” We do,
however, recommend omitting punctuation that isn’t necessary. That’s why we
leave the comma out of most simple series that aren’t confusing. 

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