John Dixon, independent medical writer and trainer in scientific writing skills, provides a useful tip for medical writers who work in MedComms.

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Recorded 30 April 2019. Produced by

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Hi, I’m John Dixon, a trainer in scientific writing, and here’s a bite that I hope may help you with your writing.

Be clear about the different types of dash [NEXT SLIDE]

There are 4 common types of dash – the hyphen, en dash, em dash and minus sign [NEXT SLIDE]

The hyphen is often used when other dashes may be more correct, and the hyphen isn’t the same as a true minus sign [NEXT SLIDE]

Let’s briefly consider the shape and position of the different dashes in relation to text…

Here are the dashes at the same size as the corresponding text

Now let’s magnify them… [NEXT SLIDE]


Here we’re looking at the dashes magnified by 7 compared with the text – and do note the font here is Arial:

* the hyphen is the shortest
* the en dash is longer
* the em dash is the longest
* the minus sign is longer than the hyphen, and usually shorter than the en dash (but this can depend on the font) [NEXT SLIDE]

* … and the minus sign is set higher than the hyphen
* The en and em dashes are set immediately adjacent to surrounding characters
* However, you can see here in Arial that the hyphen and minus sign are set with a very small space between the dash and surrounding characters compared with the en and em dashes [NEXT SLIDE]

Here in Calibri, all but the en dash are set with a very small surrounding space between dash and characters [NEXT SLIDE]

Here is a direct comparison of the lengths of the hyphen and minus sign in Arial and Calibri [NEXT SLIDE]

And this shows the difference in the height at which they’re set [NEXT SLIDE]

Now for their uses [NEXT SLIDE]

The hyphen is:

* word-making – and there are many rules and exceptions dictating how hyphens are used
* it’s word-breaking for words spanning two lines
* and also used as a hanging hyphen with prefixes and suffixes when these are used alone without attachment to a word [NEXT SLIDE]

The en dash can be used:

* to introduce notable information into a sentence … when it’s called the parenthetical dash
* it can be used to mean ‘to’ or ‘through’ for numeric and other ranges
* and to join words and names together of equal weight [NEXT SLIDE]

The em dash can be used:

* in exactly the same way as the en dash to introduce notable information into a sentence
* to indicate an omitted word or omitted data in a table
* and to set off the source of a quotation [NEXT SLIDE]

the minus sign is used as a mathematical function, but some style guides do allow the hyphen to be used for this purpose [NEXT SLIDE]

So, the hyphen is not the only dash [NEXT SLIDE]

… and in further bytes I’ll go through in more detail when to use the en and em dashes, and how to insert the various dashes using the keyboard and keyboard shortcuts.

I hope that’s helpful. For more bites to help your writing, visit

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[For the avoidance of doubt: this video is intended to be freely accessible to all. Please feel free to share and use however you like. Cheers Peter Llewellyn, Director NetworkPharma Ltd and Founder of the MedComms Networking Community activity at]