Is a comma really necessary after the last element in a list of three or more?
Consider these examples:
- Uncle Charlie left me all of his investments, real estate, and stocks.
- Uncle Charlie left me all of his investments, real estate and stocks.
Williams states that both are correct, while Strunk and White consider only the first example acceptable. With further consideration, the former makes more sense because it distinguishes three distinct elements in a will. The second example leaves more room for interpretation: did Uncle Charlie leave all of his real estate and stock investments only, or all of his investments, including real estate and stocks? The former example leaves no room for error, while the latter could be interpreted in two ways.
Use a comma after each element in a list to avoid confusion.
Many journalists and business writers will insist that no comma is necessary, or even wrong, before the and. If it comes down to it, do what your editor tells you to do, whether she is your English Professor or your boss.