Punctuation: Items in a Series and and Oxford Comma

Comma rules tend to overlap or intersect each other. Keep the rules separate and it’s easier to tell where you need a comma. A good rule to start with is the Items-In-A-Series Comma.

Commas are used to separate “items in a series,” which means a list. The lists can be simple or complex. It’s best to look at examples.

I need eggs, butter, cheese, and flour.
This is a simple list of nouns, easy to separate with commas. The first item of the series is eggs.

I need to buy gas, pick up the kids from soccer, make dinner, and pay bills.
Each item in this series is a verb phrase (a phrase that starts with a phrase). The first item is buy gas.

I’m going to print the reports, Dave is running for office, and Jill went home early.
Each item in this series is a complete sentence, but put together like this, it’s not a run-on sentence. The first item in the series is I’m going to print the reports.

The Oxford comma is a matter of debate. This is the comma before the and in a series. The Associated Press style is to not use it. Pretty much everyone else does.

My personal preference is to not use it when the items in a series are one-word items and then use it all other times. So in the above examples, I would omit the Oxford comma in the first sentence and keep it in the rest. But this may be too eccentric for practical use.