7 Common Instances of Incorrect Comma Usage: An Editing Checklist
The comma is an important component of English mechanics. It plays a crucial role in making writing clear, unambiguous, and easy to read. Unfortunately, however, correct comma usage is often neglected by many authors and even some editors. Here are seven common, comma-related mistakes you should look out for when proofreading your final draft.
1. The Comma Splice
This error occurs when two independent clauses are connected by only a comma, creating a run-on sentence.
Take the following two independent clauses.
(a) I’m a mechanical engineer.
(b) I design internal combustion engines for Ford.
A comma splice would occur if (a) and (b) were joined with only a comma:
I’m a mechanical engineer, I design internal combustion engines for Ford.
There are two correct ways of uniting (a) and (b). The first is with a semicolon. The second is with a comma in combination with a conjunction.
(1) I’m a mechanical engineer; I design internal combustion engines for Ford.
(2) I’m a mechanical engineer, and I design internal combustion engines for Ford.
Note: An independent clause is a clause that could be a complete sentence.
2. The Comma Between an Independent Clause and a Dependent Clause
This error occurs when one independent clause and one dependent clause are joined with a comma in combination with a conjunction.
Take the following clauses:
(a) He enjoys building robots.
(b) is studying to be a mechanical engineer
Here, (a) is independent, while (b) is dependent.
In this case, it is incorrect to use a comma in combination with a conjunction to join the two clauses:
He enjoys building robots, and is studying to be a mechanical engineer.
What is the correct way to connect (a) and (b)? The answer: with just a conjunction:
He enjoys building robots and is studying to be a mechanical engineer.
3. The Comma Between a Subject and Its Verb
This error occurs when a comma separates a subject from its verb.
Take the following sentences:
(a) My roommate Carlos built a cardboard boat.
(b) My roommate Carlos, built a cardboard boat.
Which of these sentences is correct? The answer: (b).
This may be confusing to some authors who were not previously familiar with this rule. Many people — even native English speakers — are not aware of the specifics of punctuation, simply assuming that commas are placed wherever a speaker would naturally pause. And in spoken English, people do sometimes pause between a subject and its verb. However, in written English, using a comma to separate a subject from its verb impedes readability and makes a sentence seem unnatural. With very few exceptions, a comma should not separate a subject from its verb.
4. The Comma Separating a Verb and Its Object
This error occurs when a comma separates a transitive verb from its direct object.
Take the following sentences:
(1) Shawna said she builds desktop computers at home.
(2) Shawna said, she builds desktop computers at home.
Which of these sentences is correct? The answer: (a).
Like in the case of a comma separating a subject from its verb, it may be difficult for some writers to spot this error intuitively. However, using a comma to separate a transitive verb from its direct object decreases readability and comes off as unnatural. It is important to remember that the rules of written English are significantly more rigorous than the guidelines of spoken English. A pause in spoken English does not always translate into a comma in written English.
5. The Comma with Restrictive Clauses
This error occurs when a restrictive clause is set off by a comma.
Take the following sentences:
(a) The desktop, that Shawna built, is valued at 1800 dollars.
(b) The desktop that Shawna built is valued at 1800 dollars.
Which of these sentences is correct? The answer: (b).
Confusion may occur since a comma should set off a nonrestrictive clause from the rest of a given sentence. The difference between restrictive and nonrestrictive clauses lies in the necessity of information. In this case, the clause “that Shawna built” is necessary information because without it, it would be unclear which desktop is valued at 1800 dollars.
6. The Missing Comma Following E.g. and I.e.
While the strict rules regarding the use of a comma after e.g. and i.e. vary across style guides, the rule of thumb for American English is to always follow both e.g. and i.e. with a comma. Contrary to popular intuition, virtually all American style guides recommend using a comma after e.g. and i.e.
7. The Missing Oxford Comma
Many sources state that the Oxford comma is optional — as long as it is either used or not used throughout a given work, it doesn’t matter. However, in American English, it is standard to use an Oxford comma. The Chicago Manual of Style, which is commonly used by book publishers, academics, and trade publications, mandates the use of the Oxford comma. Furthermore, in some cases, the Oxford comma is necessary to eliminate ambiguity. For this reason, using the Oxford comma is recommended when writing academic texts.
Take the following sentences (written without the Oxford comma):
(a) Edena’s favorite foods are chicken, chickpeas, roast potatoes and rice.
(b) Olaf’s debut novel is dedicated to all novels by Kazuo Ishiguro, “The Nicomachean Ethics” and “Cat’s Cradle.”
Both sentences could be considered ambiguous.
(a) could be interpreted to mean that Edena’s favorite foods are chicken, chickpeas, and a single dish that is composed of roast potatoes and rice. However, it could also be interpreted to mean that Edena likes these four foods (chicken, chickpeas, roast potatoes, rice) individually.
(b) could be interpreted to mean that Olaf’s debut novel is dedicated to all novels by Kazuo Ishiguro and that those two novels are The Nicomachean Ethics and Cat’s Cradle. This is ridiculous to those who are familiar with Ishiguro and the books “The Nicomachean Ethics” and “Cat’s Cradle”. However, those who are not could easily think that the only two novels written by Ishiguro are called “The Nicomachean Ethics” and “Cat’s Cradle.”
Do you need more help? Check out professional English editing services!
If you are struggling with English punctuation or grammar, you may want to consider English editing services. Online editing companies employ professional academic editors who not only correct mechanical and grammatical errors but also improve writings in terms of style, terminology, and flow. Make sure to do your research and choose a company that is highly reputable and employs experienced, qualified editors. Happy writing!
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