Grammar Tip – Commas in a Series

BizWritingTip reader: “I have heard that it is now acceptable to place a comma before the ‘and’ in a list in a sentence. Is this something that was changed recently? Can you help me out?”

BizWritingTip response: When a sentence contains three or more items in a series, place a comma before the “and” to avoid confusion or to make a clear separation.

She is educated, experienced, and highly professional. (There are three reasons we should hire her.)
It is important that writers understand the rules for commas, dashes, and colons. (There are three separate areas writers should be clear on.)

But if the separation is clear because the reader already knows the information or the information is self evident, you do not need a comma before the “and.”

The American flag is red, white and blue. (The reader understands there are three colours here.)
The train stops at Toronto, Chatham and Windsor. (The reader knows these are three separate cities.)

I trust this BizWritingTip is timely, helpful, and easy to follow.