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Business Grammar: Run-Ons, Fused Sentences, and Comma Splice Errors

We've reviewed literally thousands of client writing exercises in our business writing courses. Consistently, the most common grammar error we see in client writing across all industries and positions is the fused sentence error. (Fused sentences are also called comma splices or run-on sentences.) They refer to compound sentences that are not punctuated correctly. 

Fused sentences, run-on sentences, and comma splice errors are rampant in business writing!

Explanation

A fused sentence — also called a comma splice error or run-on sentence — incorrectly merges two independent clauses into one sentence by connecting the clauses incorrectly with a comma.

Incorrect example:
I’m sorry to hear you are not feeling well. Let’s reschedule our meeting. I’m open anytime this Thursday, if there is a particular time that will work best for you let me know.

Should I notify the operations team we need to reschedule, as well?

Correct example:
I’m sorry to hear you are not feeling well. Let’s reschedule our meeting. I’m open anytime this Thursday. If there is a particular time that will work best for you let me know. (There should be a full stop – a period – after the word “Thursday,” indicating two separate sentences.)

Should I notify the operations team we need to reschedule, as well?

Solution for the example:
Do not merge two independent clauses together with only a comma. Each thought, “I’m open any time Thursday.” and “If there is a particular time … ” should be its own sentence.

Other typical examples of incorrectly fused sentences/comma splices are:

  • Thanks for your advice, it’s exactly what I needed.
  • These proofs are great, thanks for sending them.
  • I will see you on Tuesday, I’m looking forward to our meeting.

Rules to Follow

Punctuate compound sentences comprised of independent clauses correctly by following either of these two rules:

  1. Join the two independent clauses together with a coordinating conjunction (and, but, for, or, nor, so, yet), and use a comma before the connecting word:

    ________________, and _______________.

    Example:
    He enjoys writing at work, and he is often lauded for his skill.


  2. When you do not have a connecting word (or when you use a connecting word other than and, but, for, or nor, so, or yet between the two independent clauses) use a semicolon (;)
    _____________________; _____________________.

    Example:
    Caleb often wrote proposals; Suki preferred to edit them.

 

Business Writing Tip

While rule #2 connecting independent clauses with a semi-colon is grammatically correct, it will create a longer and more complex sentence. The goal of business writing is clear, easy-to-understand writing.

You could avoid using semi-colons in your writing across your entire career, and it would be fine! Semi-colons add complexity to a sentence. They're not wrong to use, but they're commonly used incorrectly and they add visual complexity. Why bother with them when there is another strategy?

Instead of using a semi-colon and merging the independent clauses to prevent a fused sentence, simply split the independent clauses into two separate sentences. Don't fuse the sentences.


Incorrect -  The independent clauses are fused, creating a run-on sentence:

  • Caleb often wrote proposals Suki preferred to edit them.

Correct — The semi-colons connect the independent clauses:

  • Caleb often wrote proposals; Suki preferred to edit them.

Correct and visually clean — The independent clauses are two separate sentences:

  • Caleb often wrote proposals. Suki preferred to edit them.

 

Mary Cullen

About the author

Mary Cullen

Mary founded Instructional Solutions in 1998, and is an internationally recognized business writing trainer and executive writing coach with two decades of experience helping thousands of individuals and businesses master the strategic skill of business writing. She excels at designing customized business writing training programs to maximize productivity, advance business objectives, and convey complex information. She holds a B.A. in English from the University of Rhode Island, an M.A. in English Literature from Boston College, and a C.A.G.S. in Composition and Rhetoric from the University of New Hampshire.

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