Now commas are quite a bit trickier than periods. And I do see quite a few comma errors in student writing, and I feel as though part of that is because people just get nervous about commas. You know, you probably learned about commas in elementary school or middle school but you don’t really focus on them too much after that. So a lot of people either, they’re nervous to use commas, so they don’t use any, or they know that they should use commas, so they use too many. And then also, complicating matters is the fact that commas are very stylistically specific. And by that I mean, APA wants you to use commas where others types of writing don’t ask for you to use commas. So it’s important to learn where specifically APA asks you to use commas.
And there are four main places that you’ll want to use commas. The first is [reading from the slide] “after introductory clauses.” Introductory clauses provide extra information for a sentence, but aren’t really part of the main action of the sentence. For example, [reading from the slide], “Despite the delay, comma, I expect to complete the study on time.”
So this is all introductory information and using a comma helps set it apart from the main action of the sentence.
You also want to use commas on either side of non-essential clauses. A non-essential clause is a group of words that provide additional information in a sentence but aren’t necessary for the sentence to make sense. [Reading from the slide]: “Mary, the newest employee, just finished training.” It makes sense if I were to just say “Mary just finished training,” right? I could cut out this phrase from the sentence and the sentence would still make sense.
So this is called a non-essential clause and you want to use commas on either side of it to set it apart from the rest of the sentence. You want to use commas in a list of three or more. So for example, [reading from the slide], “He has written three week books, a novel, comma, a memoir, comma, and a biography.”
Now this comma right here, this comma before the word “and” is called an Oxford comma, and not all types of writing require you to use an Oxford comma, but APA does require it, so you just want to make sure you include a comma before the final item in your list.
And then finally, when you have two complete sentences but you’re joining them with a conjunction, so a conjunction is a word like “and,” “but,” “or,” words like that. When you’re using a conjunction to join two independent clauses, you want to use a comma between those two clauses.
[[Reading from the slide]: “I turned in the paper late.” That’s a complete sentence. “At least I finished it.” That’s another complete sentence, and then I have the conjunction “but” here, so I want to use this comma to separate these two independent clauses.
[Source: Walden University. https://academicguides.waldenu.edu/c.php?g=465757&p=3437931 ]