Writers use parentheses to include additional information that would impede continuity without this separation. Parentheses can enclose additional details, an aside to address the reader or information about the source of borrowed ideas in a research paper.
Phrases within parentheses often give further detail about the concepts being presented, such as: "The store was nearby (just two houses down)." Place a phrase that would otherwise qualify as a sentence -- but depends on the surrounding information for context -- within the parentheses, and insert the end punctuation after the final parenthesis, as follows: "The store was nearby (it was just two houses down)." If the parenthetical section is a full sentence, capitalize the first word of the sentence and use end punctuation within the parentheses, for example: "The store was nearby. (It was just two houses down.)"
Documentation Formats and Parentheses
In Modern Language Association format, if you use information from a source, include the last name of the author of the source along with a page number where you found the information, as follows: (Smith 3). For American Psychological Association style, include the author's last name and the date that the article was published in parentheses along with a page or paragraph number for direct quotes, as follows: (Smith, 2014, p. 2). Note that when you paraphrase information in APA style, place the sentence's end punctuation immediately after the closing parenthesis. For direct quotes, insert quotation marks before the parentheses, for example: "Writers often use such techniques" (Jefferson, 2014, para. 3).