Run-Ons and Comma Splices

GRAMMAR OFFENDER: The Run-on & Comma Splice

Now that you know the difference between a fragment and a sentence you are ready to tackle another common writing error: the run-on and comma splice. Remember, unlike the fragment, a sentence has a subject (the doer or actor) and a predicate (the action) allowing it to stand on its own as a complete thought. Fragments seem to end abruptly, and leave you wanting to ask something like “…and then what?”

What Is a Run-on Sentence?

A run-on sentence, also known as a fused sentence, is a sentence that goes on and on and needs to be broken up. Run-on sentences occur when two or more independent clauses are improperly joined. They might just seem to be the type of sentence that goes on and on without a clear point. 

Run-ons may have nothing between them, or they may have a coordinating conjunction (and, or, nor, but, for, so, yet) but not the comma that needs to accompany the coordinating conjunction when separating two independent clauses. The technical grammatical definition of a run-on sentence is one that fuses, or “runs together,” two or more independent clauses (clauses that express a complete thought and could stand on their own as full sentences) without punctuation to separate them. 

Common Causes of Run-On Sentences

We often write run-on sentences because we sense that the sentences involved are closely related and dividing them with a period just doesn’t seem right. We may also write them because the parts seem to short too need any division, like in “She loves skiing but he doesn’t.” However, “She loves skiing” and “he doesn’t” are both independent clauses, so they need to be divided by a comma and a coordinating conjunction—not just a coordinating conjunction by itself.

Another common cause of run-on sentences is mistaking adverbial conjunctions for coordinating conjunctions. For example if we were to write, “She loved skiing, however he didn’t,” we would have produced a comma splice. The correct sentence would be “She loved skiing; however, he didn’t.”

Fixing Run-On Sentences

Before you can fix a run-on sentence, you’ll need to identify the problem. When you write, carefully look at each part of every sentence. Are the parts independent clauses, or are they dependent clauses or phrases? Remember, only independent clauses can stand on their own. This also means they have to stand on their own; they can’t run together without correct punctuation.

Let’s look at a few examples of run-on sentences:

  • Often, choosing a topic for a paper is the hardest part it’s a lot easier after that.
  • Sometimes, books do not have the most complete information it is a good idea then to look for articles in specialized periodicals.
  • She loves skiing but he doesn’t.
  • The opposite is true of stronger types of stainless steel they tend to be more susceptible to rust.

All three of these have two independent clauses. Each clause should be separated from another with a period, a semicolon, a comma and a coordinating conjunction, or a dependent clause should be created (the revisions are italicized):

  • Often, choosing a topic for a paper is the hardest part. It’s a lot easier after that.
  • Sometimes, books do not have the most complete information; it is a good idea then to look for articles in specialized periodicals.
  • She loves skiing, but he doesn’t
  • The opposite is true of stronger types of stainless steel because they tend to be more susceptible to rust.

Let’s take a look at this run-on:

  • Most of the hours I’ve earned toward my associate’s degree do not transfer however I do have at least some hours the University will accept.

Here is the application of the four fixes to this problem noted above. with the revisions italicized:

  1. The first is to place a period before however and capitalize it. (Most of the hours I’ve earned toward my associate’s degree do not transfer. However, I do have at least some hours the University will accept.)
  2. If the above fix this feels like too hard of a stop between ideas, you can insert a semicolon instead and keep the lowercase. (Most of the hours I’ve earned toward my associate’s degree do not transfer; however, I do have at least some hours the University will accept.)
  3. Another fix is to create a dependent clause to lead into or follow an independent clause. (While most of the hours I’ve earned toward my associate’s degree do not transfer, however I do have at least some hours the University will accept.
  4. The other fix is to insert a comma after transfer and use but (a coordinating conjunction) instead of however. (Most of the hours I’ve earned toward my associate’s degree do not transfer, however but I do have at least some hours the University will accept.)

What Is a Comma Splice?

One type of run-on that you’ve probably heard of is the comma splice, in which two independent clauses are joined by a comma without a coordinating conjunction (and, or, but, etc.). A comma splice is similar to a run-on in that it joins two independent clauses, but it differs in that the clauses are joined by a comma. Interestingly, a comma splice is a sentence error—not a comma error, which has to do with punctuation.

Examples of comma spliced sentences

  • Every day, millions of children go to daycare with millions of other kids, there is no guarantee that none of them are harboring infectious conditions.
  • Many daycares have strict rules about sick children needing to stay away until they are no longer infectious, enforcing those rules can be very difficult.
  • Daycare providers often undergo extreme pressure to accept a sick child “just this once,” the parent has no other care options and cannot miss work.

In Review: Common Fixes for Run-ons and Comma Splices

Once you find a run-on or comma splice and notice where the two independent clauses “collide” or are “spliced,” you can then decide how best to separate the clauses, which are basically the same as with run-ons:

  1. You can make two complete sentences by inserting a period. This is the strongest level of separation.
  2. You can use a semicolon between the two clauses if they are of equal importance; this allows your reader to consider the points together.
  3. You can use a semicolon with a transition word to indicate a specific relation between the two clauses; however, use this sparingly.
  4. You can use a coordinating conjunction following the comma, and this also will indicate a relationship.
  5. Or, you can add a word to one clause to make it dependent.

In the following examples of fixed run-on and comma spliced sentences from above, notice how they have been punctuated in the following examples:

  • Every day, millions of children go to daycare with millions of other kids. There is no guarantee that none of them are harboring infectious conditions.
  • Many daycares have strict rules about sick children needing to stay away until they are no longer infectious; however, enforcing those rules can be very difficult.
  • Many daycares have strict rules about sick children needing to stay away until they are no longer infectious, but enforcing those rules can be very difficult.
  • Daycare providers often undergo extreme pressure to accept a sick child “just this once” because the parent has no other care options and cannot miss work.

Writer’s Tip

If you struggle with run-ons read your paper out loud.  The run-on sentences will trip you up: you’ll want to pause or otherwise come to some sort of end when you hit the end of an independent clause, but a run-on, with its lack of punctuation, doesn’t signal you to do that.

If you struggle with comma splices, find all the commas in your paper, look at the text before and after the comma, and decide whether they can stand alone—do they both contain a subject and a verb to make a complete thought? If so, then you have found the comma splice!