Writing Module
Commas
A comma is a
valuable punctuation
device.
Rule 1: Use commas
to separate
independent clauses.
Rule 2: Use commas
after introductory
elements that come
before the main
clause.
A comma is a valuable punctuation device. It separates structural
elements into manageable segments and gives clarity to the
meaning of a sentence.
There are rules about comma use in writing, and the misuse of
commas is a common error. This module will address some of the
most common rules.
Rules for Comma Usage
Rule 1: Use commas to separate independent clauses when they are
joined by any of the following seven coordinating conjunctions:
and, but, for, or, nor, so, and yet.
The instructor explained the assignment, yet the student still
didn’t seem to understand what to do.
Yesterday was Carol’s doctoral defense, so we took her out to
lunch to celebrate.
Rule 2: Use commas after introductory clauses, phrases, or words
that come before the main clause. Common starter words for
introductory clauses include after, although, as, because, if, since,
when, and while.
While I was reading, the dog scratched on the back door to be let
in the house.
When the rain stops falling, we will go for a walk.
Common introductory words that should be followed by a comma
include yes, however, and well.
However, you may find the process does not work.
Well, he meant to model good behavior.
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Rule 3: Use commas
to set off non-essential
elements in the
sentence.
Essential element or
not?
Does the sentence
make sense
without it?
Does it interrupt
the flow of the
sentence?
Does the sentence
still make sense if
you move it to
another spot?
Rule 4: Use commas
to separate three or
more elements.
Rule 5: Use commas
to separate coordinate
adjectives.
Rule 3: Use a pair of commas in the middle of a sentence to set off
clauses, phrases, and words that are not essential to the meaning of
the sentence.
That report, which is available only in an electronic form, is due
on Friday to the chief operating officer.
How do you know if a word, phrase, or clause is essential to the
meaning of the sentence? If you answer “yes” to one or more of the
following questions, then the element is not essential and should be
set off with commas:
Does the sentence still make sense if you leave out the
element?
Does the element interrupt the flow of words in the original
sentence?
Does the sentence still make sense if you move the element
to a different position in the sentence?
For example if you leave out the element in the previous example, it
would read:
That report is due on Friday to the chief operating officer.
The sentence still makes sense and is a complete sentence, so the
first question would be answered with a “yes.” The element is not
essential and should be off set with commas.
Rule 4: Use commas to separate three or more words, phrases, or
clauses written in a series.
The new owner promised to eliminate overtime, provide better
food in the cafeteria, and improve working conditions.
Rule 5: Use commas to separate two or more coordinate adjectives
that describe the same noun.
Coordinate adjectives are adjectives with equal status in
describing the noun.
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Coordinate
adjectives or not?
Can you reverse
the order?
Can you use and
between them?
If you answer “yes” to either of the following questions, then the
adjectives are coordinate and should be separated by a comma:
Does the sentence make sense if the adjectives are written in
reverse order?
Does the sentence make sense if the adjectives are written
with and between them?
He was a difficult, stubborn child.
Are the adjectives difficult and stubborn coordinate or noncoordinate?
If you reverse the order of the adjectives, you get:
He was a stubborn, difficult child.
The sentence still makes sense if you add and between the
adjectives:
He was a stubborn and difficult child.
The adjectives in the examples are coordinate, and a comma should
be used to separate them.
Let’s examine another example:
She often wore a gray wool suit.
Are gray and wool coordinate adjectives? If you reverse the order,
does the sentence make sense?
She often wore a wool gray suit.
Possibly. Let’s ask the other determining question to make sure. If
you add and between wool and gray, does the sentence make sense?
She often wore a wool and gray suit.
This does not make sense, so these adjectives are non-coordinate. A
comma should not be used to separate them.
This concludes the major rules about the use of commas. However,
it is more common to use commas incorrectly. This can break a
sentence into illogical segments or confuse the reader with
unnecessary pauses.
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Rule 6: Don’t use a
comma to separate a
subject from its verb.
Rule 7: Don’t use a
comma between two
verbs.
Rule 8: Don’t use a
comma between two
nouns in a subject.
Rule 9: Don’t use a
comma between the
main clause and the
dependent clause that
follows it.
Rules to Avoid Comma Abuse
Rule 6: Don’t use a comma to separate the subject from the verb in
a sentence.
Incorrect: The most important characteristic of a leader, is good
communication skills.
The comma should not be used in this sentence.
Rule 7: Don’t put a comma between two verbs or verb phrases.
Incorrect: Joe turned on the lawn mower, and ran into the bush.
The comma should not be used in this sentence.
Rule 8: Don’t put a comma between two nouns or noun phrases in
a compound subject.
Incorrect: Dave from accounting, and Eric from marketing play
softball together.
The comma should not be used in this sentence.
Rule 9: Don’t put a comma after the main clause when a dependent
clause follows it.
Incorrect: Dave was late for the meeting, because the printer
was jammed.
The comma should not be used in this sentence.
Correct comma usage is a key component in the clarity of your
writing. You have seen when commas should be used and when
they should not to be used. If you follow the basic rules provided
when writing and proofreading your papers, you should have no
problem with commas.
Return to the Graduate Success Prep Program available through
the myFranklin Web site and do the exercises for this module.
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