Comma Splices and Run-On Sentences

A comma splice or run-on sentence is two complete ideas jammed together with an incorrect comma (comma splice) or with no punctuation at all (run-on). Complete ideas need sufficient separation.

Comma Splice vs. Run-On Sentence


A comma splice consists of two complete ideas, each containing at least one subject and and one verb, that are connected with only a comma, which isn't strong enough punctuation for the situation.

The survey was too small, the results were useless.

Contrary to popular belief, a run-on sentence is NOT just an excessively long and rambling sentence.  Instead, this error consists of two complete ideas (each containing a subject and a verb) jammed together with no punctuation at all.

The survey was too small the results were useless.

Tip:  Look out for a subject pronoun (I, we, you, he, she, they, it) in the middle of a sentence.  This may indicate a comma splice or run-on sentence. Check if the sentence is using one of the following correct ways to combine the ideas together. 

 

How to Fix a Comma Splice or Run-On Sentence


  1. Break the idea with a period, exclamation point, or question mark and start a new sentence.
  2. Add a comma (,) and a connecting word (for, and, nor, but, or, yet, so).
  3. Use a semicolon (;) for closely connected ideas.
  4. Use a semicolon (;) along with a conjunctive adverb like moreover, therefore, in addition, or consequently, followed by a comma.

See below for some examples.

1. Break the idea with a period, question mark, or exclamation point and start a new sentence.


The survey was too small. The results were useless.

2. Add a comma and a connecting word, also called a conjunction (for, and, nor, but, or, yet, so).


The survey was too small, so the results were useless.

3. Use a semicolon (;) for closely related ideas.


The survey was too small; the results were useless.

4. Use a semicolon (;) along with a conjunctive adverb followed by a comma.


The survey was too small; therefore, the results were useless.
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