Comma Splice

Learn how to identify and fix comma splices

What is a Comma Splice?

A comma splice is

Related Concepts: Common Sentence ErrorCoordination & SubordinationRegisterSentenceParts of a SentenceIndependent ClausesDependent Clauses & Phrases

Comma Splice Examples

A comma splice divides two independent clauses with a comma.

John ran quickly toward the exit, he was trying to avoid his ex-girlfriend.

In the above example, the clauses on either side of the comma are independent. An independent clause is a complete idea and can stand alone as a sentence. Two independent clauses should not be separated by a comma.

To determine whether you have used a comma splice, look at the clauses on either side of the comma alone. Try it with the above example, starting with the clause before the comma:

John ran quickly toward the exit.

This can stand alone as a sentence; therefore, it is an independent clause. Now look at the clause that comes after the comma:

He was trying to avoid his ex-girlfriend.

This can also stand alone as a sentence; therefore, it is also an independent clause.

Here are several more examples. Look at each clause separately to determine whether it is independent.

I am not buying any more books, I need to read the books I already own.

Painting is my hobby, foreign policy is my passion

How to Fix A Comma Splice

There are four good options for fixing comma splices:

Option 1: Use end-mark punctuation correctly

Divide the two independent clauses with the appropriate form of end-mark punctuation. Typically use a period to mark sentence barriers, but feel free to use

  • a colon to denote a general-to-specific semantic relationship
  • a semicolon to indicate the two sentences are coequal
    • Note: Semicolons can be used to divide two independent clauses that are closely related. It’s a grammatical half-step between a comma and a period.
  • a question mark to engage thought and dialog
  • an exclamation mark to focus an insight, discovery, or declaration.
Sample Error:

John ran quickly toward the exit, he was trying to avoid his ex-girlfriend.

Edited Examples:

John ran quickly toward the exit. He was trying to avoid his ex-girlfriend.

John ran quickly toward the exit; he was trying to avoid his ex-girlfriend.*

*Note that the first word after a semicolon is not capitalized as it is technically not a new sentence.

Option 2: Use A Coordinating Conjunction to Join the Two Sentences

Writers use coordinating conjunctions (and, but, or, for, nor, so, and yet) to show readers that ideas in the two sentences are related to one another in some way.

Sample Error:

John ran quickly toward the exit, he was trying to avoid his ex-girlfriend.

Edited Example:

John ran quickly toward the exit, for he was trying to avoid his ex-girlfriend.

Option 3: Add a subordinating conjunction to one of the independent clauses to make it dependent.

When writers want to show how one idea impinges on another, they use the linguistic concept of subordination, a syntactical concept.

Sample Error:

John ran quickly toward the exit, he was trying to avoid his ex-girlfriend.

Edited Example:

John ran quickly toward the exit because he was trying to avoid his ex-girlfriend.

Option 4: Revise the sentence entirely.

Whenever you are editing the punctuation of your texts, you should take a moment to look at how many words, phrases, and clauses you are using in each sentence.

If you find you have a lot of comma splices in a draft, then it’s wise to revisit the concepts of coordination & subordination:

  • Ask yourself how you can get more words in one sentence yet keep each sentence focused on one idea that flows, that follows the given to new contract.
Sample Errors:

The fire alarm went off, we left the building.
John ran quickly toward the exit, he was trying to avoid his ex-girlfriend.

Edited Examples:

We left the building the moment the alarm sounded.
John ran to the exit to avoid his girlfriend

Are Comma Splices Always Wrong?

The Artful Sentence Fragment

In Standard Written English, a comma splice is always wrong. It’s not wrong for arbitrary reasons: it’s wrong because commas splices lead to miscommunication. and the loss of clarity—the ultimate goal of most writers, speakers, and knowledge workers.

Thus, you are wise to edit your sentences to eliminate comma splices in order to enhance your credibility (ethos) as a writer.

However, there are exceptions. In poetry, fiction, metafiction, and creative nonfiction genres, authors may intentionally break grammatical and mechanical rules.

Why? Why run the risk of alienating your readers?

Comma splices can be used to denote opposition to Standard Written English or other semiotic systems, other dialects of a language.

Comma splices might be used to draw attention to parallel clauses (“We came, we saw, we conquered.”) or to capture an informal tone for rhetorical effect.

Why do Comma Splices Matter?

Comma splices are an important error in English because they interfere with clarity in communications.

Additionally, a lack of control over punctuation, grammar, and mechanics may give your reader the sense that either the text you are writing is unimportant to you so you didn’t bother to proofread or you lack basic English skills. In other words, comma splices are a signal of your professionalism, attention to detail, and mastery of Standard Written English.

Comma splice errors undermine your tone, voice, and persona. Worse yet even a single comma splice on a paper written for school may merit a lower grade. In work settings comma errors can lead to expensive litigation.

End-Mark Punctutation

Sentences are governed by punctuation rules, and the comma splice is one of the most frequent and important errors made by aspiring writers.

The rules (aka conventions) that govern commas do not permit the comma to serve as a form of end-mark punctuation. Rather, in Standard Written English, only the period, exclamation point, question mark, semicolon, or colon can serve as end-mark punctuation.

Instead, a comma is a form of punctuation that is used within sentences to indicate how words relate to one another in a sentence.

What are Common Reasons for Comma Splices?

Comma splices may occur when you’re writing quickly because you may write out your thoughts without noticing that the sentences are running together.

Because punctuation and conjunctions help readers make sense of the relationships between clauses and words in writing, you should apply appropriate grammar and punctuation rules when editing your drafts. This task typically requires you to proofread after you’ve gotten all your thoughts out on the page. For many writers, waiting to proofread until after drafting allows them to stay in the flow of getting thoughts onto the page.

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