Coming in at number 15 on our list of the 20 most common grammar errors is the lack of commas in a series. This is actually going to be a short post because a ton of information exists on this topic, so at the end of this post I have a list of resources you can refer to. To Oxford or Not
Americans are inherently lazy when it comes to punctuation, thus stuff gets left out all the time, such as the Oxford comma.
According to the Oxford Dictionary, “The Oxford comma is an optional comma before the word ‘and’ at the end of a list.” Interestingly, on the other side of the pond (England) the majority of writers are anti-Oxford. In the U.S., it’s a mixed bag with more on the Oxford side of things.
I am, of course, pro-Oxford comma. It adds clarity. And when in doubt, just use it!