Parentheses or em-dashes? How do you decide?
Good writers use parentheses and em-dashes skillfully to tighten and strengthen their prose. Although a writer’s individual style—together with the information or message to be conveyed—determines how these marks are used, some guidelines can suggest which mark to choose in a specific instance.
Here are the basics. Use parentheses to set off matter that you want to minimize or that is helpful but not essential. Use em-dashes to highlight information or give emphasis to matter that is independent of the main sentence. Em-dashes may also be used to tack on an important afterthought at the end of a sentence. To remember this general rule, think em. Em-dashes emphasize. Parentheses minimize. Following are some examples from Reading Law: The Interpretation of Legal Texts.
Ex.: A social-security disability claimant was capable of performing her old job (that of an elevator operator), but her old job was no longer available in the national economy.
Ex.: That is why we vote (directly or through our representatives) on what the law ought to be, but leave it to experts of interpretation called judges to decide what an enacted law means.
Ex.: The word or phrase at issue is a statutory term used in a particular field of law (to which the statute at issue belongs).
In each of these sentences, the material in parentheses is interesting and informative, but it could be omitted without losing anything. Use parentheses and parenthetical material sparingly.
Ex.: The prosecutors argued that if a convicted criminal is accidentally released—even by the intentional action of a person with authority to release him—he is considered to have escaped.
Ex.: There may be nothing to the contrary anywhere in the document—even nothing that could be thought to be to the contrary.
Ex.: When drafters use shall and may correctly, the traditional rule holds—beautifully.
Notice that the material set off by em-dashes enhances the rest of the sentence. Without the em-dashes and the information, the sentences are weaker.
That’s the key to choosing between parentheses and em-dashes. If it’s a “by-the-way” bit of information, tuck it inside parentheses. If it’s kind of a zinger, draw attention to it with those long dashes.
Many writers harbor a prejudice against dashes. But they are genuinely useful—even indispensable—to the writer who cares about rhythm, variety, and emphasis. Some writers simply are unaware of the typographical differences between hyphens and the two types of dashes. I highly recommend Matthew Butterick’s Typography for Lawyers as a terrific source for the typographic nuances and keystroke tricks for these marks and myriad other formatting issues. Here’s just a snippet of his advice: “En and em dashes are often approximated by typing two or three hyphens in a row (– or —). Don’t do that. Use real dashes.”
If you learn how to use dashes well (for example, learning how to insert them in your documents easily, knowing never to use more than two in one sentence, etc.), you’ll wonder how you ever did without them.
The Winning Brief 371–73 (3d ed. 2014).
The Redbook: A Manual on Legal Style §§ 1.35–1.40, at 28–33; §§ 1.51–1.53, at 40–42 (3d ed. 2013).
Legal Writing in Plain English 179–81 (2d ed. 2013).
The Chicago Manual of Style § 6.82, at 333–34 (16th ed. 2010).
Matthew Butterick, Typography for Lawyers 48–49 (2010).
Next week: the en-dash, the em-dash’s misunderstood little brother.