When you refer to authors within the body of your paper, you place only the year in parenthesis. Many of our clients add a comma after the closed parenthesis, but that is not always necessary. APA does not recommend using this comma, unless the structure of the sentence calls for a comma there. Here are some examples:
Standard APA format
- Peterson and Williams (2009) explain that some individuals use a comma too frequently.
Sentence structure where a comma is warranted
- According to Johnson and Miller (2013), students use commas after introductory phrases.