We typically use commas to separate items in a series, and in journalism, we omit the comma before the conjunction, (usually "and," but can be another joining word). Here's an example, with the series underlined:
CORRECT: He typically eats rice, beans and ice cream for dinner every night.
Sometimes, however, the need for clarity requires us to use semicolons. Check out this example:
INCORRECT: She has lived in three state capitals: Sacramento, Calif., Richmond, Va., and St. Paul, Minn.
See the problem? This is a list of three cities, but because there are commas between each city and state, it looks like a list of six places. In cases like this where one or more items within a series contain commas, we separate the items using semicolons, like this:
CORRECT: She has lived in three state capitals: Sacramento, Calif.; Richmond, Va.; and St. Paul, Minn.
Sometimes, the need for clarity also forces us to use a comma before the "and" in a series:
UNCLEAR: The author said her main sources of inspiration were her parents, Fido and her priest.
Uh oh, we just said her parents were a dog and a priest - not what we meant. Here, the need for clarity makes the comma before the conjunction not only acceptable, but desirable:
CORRECT: The author said her main sources of inspiration were her parents, Fido, and her priest.
© Holly A. Heyser
