One of the biggest controversies in writing in English is the use of a comma before and. This comma is known as the serial comma, or Oxford comma. One of the reasons that this little punctuation mark is so controversial is that it is not a requirement of grammar; it is a style consideration. Two major styles differ on the use of the serial comma: AP (Associated Press) and APA (American Psychological Association). Simply put, APA requires a serial comma and AP only uses it if needed for clarity.
BTW, MLA also requires a serial comma, so you English majors better get used to putting a comma before and in a series.
Comma before and in APA style
APA requires a serial comma because it is a scientific style and is focused on accuracy. APA does not like to leave things up to the individual writer’s discretion. Just as a scientific experiment must report every detail of the apparatus used to conduct the experiment, APA style expects that the writing does not allow for any ambiguity of meaning. In section 4.03 of APA 6, the serial comma is clearly required: “between elements (including before and and or) in a series of three or more items.” In fact, APA even requires the serial comma to be included in in-text references: (Smith, Smith, & Jones, 2016).
Comma before and in AP style
AP is a journalistic style, so it is focused on brevity, but it also needs to ensure accuracy, so it leaves the decision up to editors. Here are two examples of how AP might treat the need for a comma before and from the blog AP vs Chicago:
- I like to pet kittens, puppies and bunnies.
- I had orange juice, toast, and yam and kegs for breakfast. (Note: This is the cruelty-free version of AP’s classic “ham and eggs” example.)
Notice how the second version needed the comma before the first and because the second and denoted a pair that was not simply two more items in the series.
Grammar Girl points out that journalistic styles are always looking to save space, which is why they allow writers to drop the serial comma. She writes that she prefers the use of the serial comma because of the clarity.
And what’s the big deal on saving space in journalism? Well, in the old days, type was set by hand, letter by letter with bits of metal. Each item had to be manually inserted into a line of type. So an extra comma was a lot more extra work than a keystroke.
Comma before and in Chicago style
Speaking of Chicago, it “highly recommends” the use of the serial comma (6.08). Like APA style, Chicago is focused on scientific writing and precision, so it leaves little up to the writer’s discretion.
So what’s the bottom line?
Each of the major academic styles mentioned here, APA, MLA, and Chicago, use the serial comma. For academic writing, then leave it in. Check with the journal’s style if you are writing for a publication. In AP style, think about clarity. With an in-house publication, you should have an in-house style that all writers follow. Probably the number one thing to standardize is the use of the serial comma.