Common Problems (Part 37 of 50)

In books, we put a comma before the final conjunction in a series such as Mary, Thomas, and Philip; in magazine articles, we usually don't.

Most magazines and newspapers use the Associated Press Style Guide (AP), which is usually updated annually.

Book publishers use the Chicago Manual of Style (CMS or CMOS), which has been around since 1906 and is updated irregularly. The 15th edition came out in 2003 and the 16th in 2010. Notice the difference in the two styles:

* He bought spaghetti sauce, noodles and a package of brownie mix. (The CMOS would insert a comma after noodles.)

* He peeled back the lid, snared a wing and offered it to Cynthia.

* Both of them are angry, hurt and eager to fight.

Think clarity first. Sometimes even the AP inserts a comma before the final conjunction. The classic example goes like this: He willed his estate to Tom, Mary and Jim. Without the comma following the name Mary, it means Tom receives half and Mary and Jim share the other 50 percent. If the author intends it to be divided into thirds, it would read: . . . Tom, Mary, and Jim.

Two things determine whether to use the serial comma. 

First, write for clarity. 

Second, consistently follow the AP or CMOS style guides.