Parentheses

an icon showing opening and closing parenthesesParentheses are most often used to identify material that acts as an aside (such as this brief comment) or to add incidental information. Use them sparingly in academic prose: generally, your essay should be tightly enough written that material either belongs because it is central, or does not belong in there at all.

Key Takeaway

It is almost never appropriate to put evidence in brackets since brackets signal incidental material: the evidence that supports your argument is the basis of the whole essay, not incidental to it.

 

Other punctuation marks used alongside parentheses need to take into account their context. If the parentheses enclose a full sentence beginning with a capital letter, then the end punctuation for the sentence falls inside the parentheses. For example:

Typically, suppliers specify air to cloth ratios of 6:1 or higher. (However, ratios of 4:1 should be used for applications involving silica or feldspathic minerals.)

If the parentheses indicate a citation at the end of a sentence, then the sentence’s end punctuation comes after the parentheses are closed:

In a study comparing three different building types, respirable dust concentrations were significantly lower in the open-structure building (Hugh et al., 2005).

Finally, if the parentheses appear in the midst of a sentence (as in this example), then any necessary punctuation (such as the comma that appeared just a few words ago) is delayed until the parentheses are closed.

You can also use parentheses to provide acronyms or full names for acronyms. For example, “We use the MLA (Modern Language Association) style guide here,” or “The Modern Language Association (MLA) style guide is my favorite to use.”

Remember, parentheses always appear in pairs. If you open a parenthesis, you need another to close it!

Note: In technical writing, there are additional conventions for using parentheses, which can be more nuanced. While we won’t discuss those conventions here, it’s important to bear their existence in mind, especially if you’re considering going into a more technical field.

Practice

Have the parentheses been used conventionally in the following sentences? Standardize where necessary.

  1. (Escobar et al., 2014) wrote about this phenomenon in their most recent paper.
  2. NASA (National Aeronautics and Space Administration) just announced three new initiatives.
  3. Michael lost the lab rat. (He also lost his temper).
  4. Helena took the viola compositions (her favorites) and gave Davi the violin pieces.