Writing Quick Tips: En Dash and Em Dash
As many of have said before me, academic writing generally isn't of the best quality. Part of it is due to the very neutral, unbiased tone which is good for science but dull to read. But more pressing is the lack of proper use of good sentence mechanics. Editors fix a lot of them, but it's good to learn how to get things right from the start, and we can begin by discussing some simple punctuation: en dashes and em dashes.
En dashes (–) and em dashes (—) are related to the hyphen (-), but used differently. The two dashes get their name from their widths: the en dash is roughly the width of a capital N, the em dash roughly the width of a capital M.
Most people tend to use a hyphen, but hyphens aren't appropriate in many cases. There are a lot of different uses for each that can get pretty specific, but here I just want to focus on ones that are most related to the sciences.
The en dash is one of the more versatile dashes. There are many situations in which it should be used, but here are the two main situations:
- For a number range (e.g., "Scores ranged from 1–3")
- When talking about a dyad (e.g., "Parent–child interaction" [using a hyphen implies you're talking about a child who is a parent, a "parent-child"])
The first use is by far the more common in scientific writing, and the more forgiving to switch with a hyphen. The second still comes up a lot in scientific writing, and it irks those of us who know that a hyphen is inappropriate. While readers will still know what you mean if you use a hyphen (generally), using en dashes adds some polish and pushes you to be more aware of other pieces of sentence structure and mechanics.
The em dash has less use in academic writing, and it's used fairly sparingly in writing more generally. But, it can really help with sentence organization and flow when it's used properly.
Em dashes are frequently replaced by parentheses, which do not serve quite the same function. An em dash allows you to basically have a brief sentence within a sentence, usually as an aside. For example: "An analysis of variance—or ANOVA for short—allows you to compare the means of several groups at once." Most writers tend to leave out any space before or after an em dash, instead having it directly next to the surrounding words.
That's all the detail I'll give here, as many of the other use cases come up infrequently in scientific writing.
Many of you are probably wondering "Alright, I know how to use them, but where do I find them? They're not on the keyboard." If you're using a word processor, you'll find them somewhere within an "Insert" menu (e.g., MS Word has Insert > Symbol > More Symbols... > General Punctuation). You can often assign a keyboard shortcut to each in a word processor to make things easier as well.
Have questions about the use of en and em dashes? Want tips on how to use other punctuation? Let me know in the comments!
For more on good mechanics in scientific writing, I highly recommend "How to write a lot: A practical guide to productive academic writing" by Dr. Paul J. Silvia.