Where do you put the comma with PhD?

You put the comma after "PhD" when it's used as a title or abbreviation after someone's name.

Examples:

* John Smith, PhD, presented his findings at the conference.

* Jane Doe, PhD, RN, is a leading expert in her field.

Here's why:

* The comma separates the name from the title or abbreviation.

* It helps to avoid confusion and ensures the title or abbreviation is clearly identified as such.

However, if "PhD" is used as a noun in a sentence, you don't need a comma:

* She earned her PhD in physics.

* The PhD candidate is working on a groundbreaking project.