Parentheses typically enclose extra information: either citations, which provide source details readers may or may not need or act on, or an extra thought or illustrative idea that did not warrant full elaboration in the text. As helpful as information in parentheses can be, it also is an interruption to the regular text, so keeping it to the point is ideal.
To that end, here are some things that should be done in parentheses that should not be done in regular text:
- Use an ampersand (&) in place of and in citations (and only in citations). For example, a citation for Solo and Skywalker (1977) in text would be (Solo & Skywalker, 1977) in parentheses.
- What would be versus in text is abbreviated vs. in parentheses (e.g., the relative heights of jawas vs. ewoks), unless one is referring to court cases, in which versus is abbreviated v. (e.g., the unlawful imprisonment suit of Organa v. The Empire).
- Other standard Latin abbreviations should also be used in parentheses rather than written out:
e.g. for for example (e.g., the Imperial traffic stop failed to apprehend the runaway droids)
i.e. for that is (i.e., those were the droids they were looking for)
viz. for namely (viz., C-3PO and R2-D2)
cf. for compare (cf. the successful apprehension of rebels during the Cloud City mission)
etc. for and so forth (Han Solo, Princess Leia Organa, C-3PO, etc.)
Please note in the examples that commas are used with Latin abbreviations where they logically would go if the phrases were written out. To help, here is a handy printable guide to Latin phrases.