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Proper sentence structure is key to clear writing, but sometimes sentences either run together or are incomplete. Run-on sentences occur when two independent clauses are improperly joined, while sentence fragments are incomplete thoughts. Identifying and fixing these issues can improve the clarity and flow of your writing.

Run-On Sentences

A run-on sentence occurs when two or more independent clauses (also known as complete sentences) are connected improperly.

In some cases, there might be no punctuation between the independent clauses.

         I love to write papers I would write one every day if I had the time.

In this example, there are two complete sentences:
  • Sentence 1: I love to write papers.
  • Sentence 2: I would write one every day if I had the time.
In some cases, a comma might separate the two independent clauses.

         I love to write papers, I would write one every day if I had the time.

This is known as a comma splice, which is a special type of run-on sentence.

Correcting Run-On Sentences

You can correct a run-on sentence by connecting or separating its parts correctly. There are several ways to connect independent clauses.

Use a Period

The easiest way to fix a run-on is to split the sentence into smaller sentences using a period. This revision works especially well with longer sentences. Check to make sure that this solution does not result in short, choppy sentences.

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  Run-On Sentence: I love to write papers I would write one every day if I had the time.

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  Revision: I love to write papers. I would write one every day if I had the time.

Use a semicolon

Inserting a semicolon between independent clauses creates a grammatically correct sentence. Using a semicolon is a stylistic choice that establishes a close relationship between the two sentences.

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  Run-On Sentence: I love to write papers I would write one every day if I had the time.

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  Revision: I love to write papers; I would write one every day if I had the time.

Use a comma and a coordinating conjunction

A comma, paired with a coordinating conjunction (like "and” or “but”), corrects a run-on sentence. This method emphasizes the relationship between the two clauses.

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  Run-On Sentence: I love to write papers I would write one every day if I had the time.

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  Revision: I love to write papers, and I would write one every day if I had the time.

Use a subordinating conjunction

Turn one of the independent clauses into a dependent clause. A subordinating conjunction (like "because" and "although") connects two clauses to create a complex sentence. This option works to cement the relationship between the two parts and may improve the flow of the clauses.

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  Run-On Sentence: I love to write papers I would write one every day if I had the time.

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  Revision: Because I love to write papers, I would write one every day if I had the time.

Use a semicolon before a transitional expression and a comma after it

Some comma splices occur when a writer attempts to use a transitional expression (like “therefore”) in the middle of a sentence. To fix this type of comma splice, use a semicolon before the transitional expression and add a comma after it. 

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  Run-On Sentence: I love to write papers I would write one every day if I had the time.

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  Revision: The results of the study were inconclusive; therefore, more research needs to be done on the topic.

Sentence Fragments

A sentence fragment is a group of words that doesn’t make a complete sentence because it’s missing a necessary part, like a subject or a verb, or it doesn’t express a full idea.

Correcting Sentence Fragments

Fragments can be corrected by identifying the missing element and including it in the sentence.

Add a Subject

Here is an example sentence fragment without a clear subject.

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Sentence Fragment: Shows no improvement in any of the vital signs.


In this example, who shows no improvement? Adding a clear subject will correct the sentence fragment.

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Revision: The patient shows no improvement in any of the vital signs.

Add an Action

Here is an example of a fragment with a missing predicate, or action.

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Sentence Fragment: The doctors, who were using peer-reviewed research articles that contributed to the body of knowledge in their fields, which was obstetrics.


Although the sentence is quite long, it still contains no action. What are the doctors doing? Once identified, the sentence can be corrected by adding an action.

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Revision: The doctors, who were using peer-reviewed research articles that contributed to the body of knowledge in their field, improved their knowledge of obstetrics.

Key Takeaways

By identifying and correcting run-on sentences and sentence fragments, you can significantly improve the readability and flow of your writing. Remember, clear writing not only conveys your message more effectively but also engages your readers and enhances their understanding.

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