Your example correctly uses the Oxford comma.
But the answer to your question regarding when one should use an Oxford comma isn’t so simple:
One reason why The YUNiversity supports the Oxford comma is that it removes confusion and ambiguity from sentences. For instance, there is this famous example that made its rounds on the Interwebs:
Using the Oxford comma, we have four people: JFK, Stalin, and two strippers.
Without the Oxford comma, we can have either four people or two people (JFK and Stalin, who are strippers). Both interpretations are valid.
A debate on whether the Oxford comma is even necessary persists because there are, to be fair, many instances in which the Oxford comma either creates (or doesn’t resolve) ambiguities. For examples of these cases, turn to Wikipedia.
Many newspapers (as seen above) do not support the Oxford comma because—as the theory goes—they have always been in the business of saving as many characters (including “non-essential” punctuations) as possible. After all, unlike websites, printed newspapers are limited in terms of printable space, so every letter, character, and space matters.
- In American English, the Oxford comma is standard in most non-journalistic writing. Therefore, you should use it in your essays for school.
- In British English, the Oxford comma is used much less frequently.
As you decide for yourself whether to endorse or shun the Oxford comma, heed this helpful advice:
That’s good advice. Right, Ezra?
(JFK, Stalin, and strippers source: imgur; Ezra Koenig GIF source: We Heart It)