Parentheses are punctuation marks used to set off information within a sentence. There are several uses for parentheses that are particular to APA style:
Example: Cub Foods sells twice as many gluten-free products as their competitors (see Table 3).
Example: Cooper (1993) attempted to disprove evolution in her article, "Ain't No Ape."
Example: It was clear that Hong Kong had been culturally colonized by the West (Gouper & Finn, 1987).
Example: Boomer and Watts (2003) insisted that "there was little that could save NATO in its current state" (p. 54).
Example: Douglas (1988) was a strong believer in the personal learning community (PLC).
Example: St. James University offered courses in (a) dental repair, (b) radioactive-spider testing, (c) peach cobblering, and (d) fairy tale indexing.
For more information about parentheses usage, check out section 4.09 of the APA manual.
Example: Smoking causes cancer (American Lung Association [ALA], 2004).
Example: Research has shown that students prefer a whiteboard to a chalkboard (Christensen et al., 2004; Lewing, 1994)