II. Run-on Sentences/Comma Splices/Fused Sentences

You are not allowed to join together two sentences (independent clauses) with a comma.

For example, you can NOT do the following:

INCORRECT: My head hurts, I am going to take an aspirin.

Both “My head hurts” and “I am going to take an aspirin” could stand on their own as sentences.  Thus, they are called independent clauses, and you cannot join two independent clauses with a comma.  This error is usually called a comma splice or a run-on sentence.

You CANNOT fix the comma splice by eliminating the comma:

INCORRECT: My head hurts I am going to take an aspirin.

This error is called a fused sentence or a run-on.

There are four ways to fix a comma splice or fused sentence (use the one that makes the most sense and/or sounds the best to you).

A) Separate the two independent clauses with a period:

My head hurts.  I am going to take an aspirin.

B) Join the two independent clauses with a comma AND a coordinating conjunction (and, but, or, nor, for, so, & yet):

My head hurts, and I am going to take an aspirin.

Or

My head hurts, so I am going to take an aspirin.

C) Join the two independent clauses with a semicolon or a semicolon followed by a transition word or phrase:

My head hurts; I am going to take an aspirin.

Or

My head hurts; therefore, I am going to take an aspirin.

D) Place a dependent word (such as after, although, because, before, even though, if, since, unless, until, when, or while) at the beginning of one of the clauses, which will change it to a dependent clause thus eliminating the problem:

Because my head hurts, I am going to take an aspirin.

NOTE:  If the dependent clause comes first, put a comma after it.  If it comes second, do not set it off with a comma unless it is nonessential information.