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Clarifying the Comma: Independent Clauses & Compound Predicates 

Early in my career, a potential employer asked me what the most common error I saw in editing was. I replied, “Commas. No one knows how to use them.” 

Over the years my answer has remained the same. Comma rules are numerous and complicated. There are plenty of exceptions, and not all the rules are governed by grammar or usage. Some rules are simply a matter of style. Love it or hate it, Eats, Shoots & Leaves is popular for a reason.

Here’s an example of the confounding comma: A fellow editor once noted that writers often do not insert a comma before a conjunction when it introduces an independent clause. Instead, they added, writers insert a comma in a compound predicate where we typically do not use one. This leads us to ask: Is there a growing misunderstanding of comma rules? 

The short answer is no, but beware of exceptions to these rules! 

It’s still the case that, in general, two independent clauses joined by a conjunction take a comma before the conjunction. If the two clauses are short enough and no misunderstanding is possible, the comma can be omitted. It’s also still the case that a compound predicate does not take a comma before the conjunction— unless there’s a potential misreading that the comma would clarify.

There: two rules with two exceptions. One rule puts a comma in unless it’s not needed, and the other omits the comma unless it’s needed. No wonder writers are confused!

This is the reason that copyeditors and proofreaders are necessary. Some writers are ignorant of punctuation (and other) rules; others know the rules but are too close to their work to see the errors. Either way, they make our work necessary. We know that a single comma can change meaning, and part of our job is to protect writers from unintended meanings.

A version of this article originally published in the June–July 2012 issue of Copyediting newsletter.


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