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Avoid This Simple “Comma Splice” Error

In 2010 one of the most common, surprising errors I saw in people's writing was run-on sentences made up of two short sentences. Here are examples:

  • Thanks for your help, it's exactly what I needed.
  • I will see you on Friday, I'm looking forward to lunch.
  • These examples are great, thanks for sending them.
  • My interview is tomorrow, we'll see how it goes.

Each of those items is two sentences. Each item is incorrect according to all style guides. 

Why do intelligent people make the error? I think people worry that they will come across too informally or too plainly if they use such short sentences. They believe using 4-to-6-word sentences, especially two of them in a row, can't be professional. 

But two short, crisp, clear sentences in a row are professional and punchy.

Some people call the error a "comma splice," since the sentences are spliced incorrectly, using a comma. To correct the errors, replace each comma with a period (full stop). Or for a breezy tone, use a dash, like this:

  • Thanks for your help–it's exactly what I needed.
  • These examples are great–thanks for sending them.
  • My interview is tomorrow–we'll see how it goes.

This example works better with a period than a dash:

  • I will see you on Friday. I'm looking forward to lunch.

The two sentences above don't have the same connection the other examples have. It would be more powerful to write the sentence below if it communicates accurately:

  • I am looking forward to lunch on Friday.

You can also use a semicolon to connect the two sentences, but I do not recommend it for the examples above. Semicolons should be used sparingly to link closely related sentences, often with words such as nevertheless and however. Read my post "In Defense of Semicolons" for examples.

Here is what I hope you do: Avoid the comma splice, it's a real error.

Did you catch the error I just made?

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By Lynn Gaertner-Johnston

Lynn Gaertner-Johnston has helped thousands of employees and managers improve their business writing skills and confidence through her company, Syntax Training. In her corporate training career of more than 20 years, she has worked with executives, engineers, scientists, sales staff, and many other professionals, helping them get their messages across with clarity and tact.

A gifted teacher, Lynn has led writing classes at more than 100 companies and organizations such as MasterCard, Microsoft, Boeing, Nintendo, REI, AARP, Ledcor, and Kaiser Permanente. Near her home in Seattle, Washington, she has taught managerial communications in the MBA programs of the University of Washington and UW Bothell. She has created a communications course, Business Writing That Builds Relationships, and provides the curriculum at no cost to college instructors.

A recognized expert in business writing etiquette, Lynn has been quoted in "The Wall Street Journal," "The Atlantic," "Vanity Fair," and other media.

Lynn sharpened her business writing skills at the University of Notre Dame, where she earned a master's degree in communication, and at Bradley University, with a bachelor's degree in English.

17 comments on “Avoid This Simple “Comma Splice” Error”

  • Thanks, Lynn. I had been searching for online content on the subject for quite some time. The detailed description provided by you will go a long way in helping me get rid of some of the errors, I make.

  • I put this into practice today. I like it. (Normally I would have placed a comma on the first sentence.) However, I do question my use of parentheses here.

  • Hi, Pete. Good for you!

    Your sentence in parentheses is punctuated correctly. But you need to ask yourself whether the sentence is actually an aside, that is, information slightly off the topic or outside the flow of your ideas.

    I would not have used the parentheses because the sentence seems on topic and in the flow.

    What was your concern?


  • Hi Lynn,

    My concern was it felt more of a thought than a statement, and I wasn’t sure that that could be expressed as such. Hence, the parentheses.

    Of course after reading your reply it is easy for me to agree. The parentheses should have been omitted.

    Thanks for all your great tips!


  • Hi, Lynn!

    Thanks for this post. Although I very much like the dash suggestion, I would like to offer a different perspective on the use of a semicolon versus a period.

    If my experience is anything like that of other writers, I tend to comma-splice certain sentences because the ideas are so closely related that using a period makes the separation feel awkward. When I read your corrected examples, the unnatural feeling was strong enough that I felt myself pause to think about why it seemed somewhat strange. As a personal preference, I feel that a semicolon would have felt less disruptive to the flow of the idea less and made for smoother reading.

  • Hi Lynn,
    I’m looking for some tips about business writing. It seems that I have found the right place. Thanks very much!

  • For the first example “Thanks for your help, it’s exactly what I needed.”, I think it can also be corrected with a subordinate clause.

    Thanks for your help, which is exactly what I needed.

  • Hi, Sapphire. You are right about the subordinate clause. It it correct. However, I don’t choose it because I like each idea to stand solidly on its own. The content in the “which” clause doesn’t get the same notice that it does in an independent clause.

    It’s a personal preference. Again, yours is correct too.

    I am glad you discovered this blog. Thanks for commenting!


  • Well, Damion, you did not make the error in your comment!

    Good luck with your editing.


  • Hi, Anne. Your comment inspired me to grab my illustrated “Elements of Style” and look for the relevant discussion.

    Here is the exact principle from the source:

    “An exception to the semicolon rule is worth noting here. A comma is preferable when the clauses are very short and alike in form, or when the tone of the sentence is easy and conversational.”

    The examples the authors offer are:

    “Man proposes, God disposes.”
    “The gates swung apart, the bridge fell, the portcullis was drawn up.”
    “I hardly knew him, he was so changed.”
    “Here today, gone tomorrow.”

    The “easy and conversational” aspect of Strunk and White’s rule is the one that most applies to my argument. However, reviewing Strunk and White’s examples, I would say they are more poetic and alike in form than the sentences most of us professionals write.

    My thoughts: Use a period or a semicolon.

    Thanks for asking your interesting question.


  • I remember reading an exception in _The Elements of Style_ that said if two independent clauses are very short and alike in form, you can join them with a comma. Any thoughts?

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