I’ve often wished that knowledge of commas was required to get a degree. Of course, this will never happen. On the other hand, you may need commas to describe your degrees, which is to say that you need commas when listing degrees after a name. Take a look at this sample.
The lead researcher was John P. Johnson, PhD, from the University of Florida.
See the commas? When degrees are listed after a name, they act like a form of parenthetical expression that provides supplemental information about the person. And like all parenthetical expressions, they are separated from the rest of the sentence with commas.
Here, the degree provides non-essential information. Although it might be important to know what degrees a person has, that information isn’t necessary to understand the idea being communicated. Furthermore, we can remove it without losing essential information and without making the sentence ungrammatical. This is a good clue that the information is parenthetical and needs commas.
This is true regardless of the number of degrees. Notice the commas before, after, and between the degrees in this sample:
Thomas Bixler, DDE, MBA, will speak at tonight’s meeting.
And it is true if you write out the degree instead of using the abbreviation, as shown here:
The department head, Fred Fredricks, Doctor of Economics, was found guilty of larceny.
These cases show how to use commas when the degree title is not part of the grammatical sentence. However, sometimes the title is part of the grammatical sentence, in which case no commas are needed, as in this example:
I went to Harvard for my PhD in English.
Put all this together, and you get Zen Comma Rule AF: Put commas around titles if they are not part of the grammatical structure.
Need help with commas? Get Zen Comma, a guide to the 17 major uses and misuses of commas, available in PDF and Kindle formats. Read more about Zen Comma.