How to Identify Run-Ons and Comma Splices for the Praxis Core Exam

By Carla Kirkland, Chan Cleveland

Grammar is usually a tricky subject for Praxis Core test takers. Although you probably remember the term run-on from school, you may not be 100 percent sure what it means. Many people mistakenly believe that a run-on sentence is just a sentence that is too long, but that’s not actually what the term means.

A run-on sentence is a sentence wherein two (or more, in especially messy cases) independent clauses have been placed next to each other without being properly joined. Just as the bones in your body need to be connected to one another with ligaments, independent clauses must be connected to one another with the proper combination of conjunctions and/or punctuation.

The run-on sentence’s ugly cousin is the comma splice. The comma splice is a run-on sentence that attempts to join two independent clauses with only a comma, when more than just a comma is necessary.

In short, both run-ons and comma splices are grammatical errors, and very similar ones — the difference is that a comma splice has a comma in it and a run-on doesn’t.

In case all that was about as clear as mud, here are some examples. Start by examining the correct, complete sentence “Shakespeare is my favorite writer, because his characters are the most memorable.” This sentence consists of two independent clauses (“Shakespeare is my favorite writer” and “his characters are the most memorable”), joined with the conjunction because and a comma before the conjunction.

Using a comma and a conjunction is the most common way to correctly join two independent clauses. A comma splice is when the writer puts in just the comma without the conjunction, and a run-on is when the writer puts nothing at all between the two clauses, as in these sentences:

  • Comma splice: “Shakespeare is my favorite writer, his characters are the most memorable.”

  • Run-On: “Shakespeare is my favorite writer his characters are the most memorable.”

Most grammar tests for older students or adults don’t bother throwing in too many run-ons, because they’re easy to spot. But test-writers just love to throw comma splices at you! Learn to spot a comma splice from a mile away, and your score will shoot up significantly solely due to your acquiring that one skill!

Which of the following sentences is not grammatically correct?

  • (A) Before your friends get here, we should pick up some snacks.

  • (B) That movie was too long, I almost fell asleep.

  • (C) If I don’t get this question right, I’m going to be deeply ashamed.

  • (D) I’m afraid of that dog, so I’m going to walk the long way home.

  • (E) The sun is warm, the sky is blue, and I’m happy.

The correct answer is Choice (B). That sentence presents two independent clauses joined with only a comma, making it a comma splice and the only one of the five choices that is not a correct sentence. Choice (A) presents an independent clause preceded by a dependent clause, with a comma between the two, which is correct.

Choice (C) links two independent clauses by placing a comma between them and the subordinating conjunction “if” at the beginning of the first clause, which is correct. Choice (D) links two independent clauses with a comma and a coordinating conjunction, which is correct.

Choice (E) presents three independent clauses, and although there is only a comma between the first two, there’s a comma and a conjunction between the second and third, so that choice is correct as well.