Do you perpetrate run-on sentences?

Probably not. And it’s not a crime. But perpetrating a run-on sentence sends a message about you: You’re less than fully literate or you don’t proofread well. In this post I’ll define terms, highlight types of run-ons, and offer suggestions for fixing them.

A run-on sentence isn’t just any long or awkward sentence. A run-on sentence results from improperly joining independent clauses. An independent clause is a group of words that could be a grammatical sentence by itself. For example, these are both independent clauses:

• I understand there must be rules.
• Many forms of writing have rules.

A true run-on sentence joins independent clauses without punctuation or a conjunction:

• I understand there must be rules many forms of writing have rules.

I almost never see this in legal writing.

But it’s also incorrect to join two independent clauses with only a comma. When you do that, you create a type of run-on sentence called a comma splice:

• I understand there must be rules, many forms of writing have rules.

I do see comma splices in legal writing, but rarely. To properly join two independent clauses, you could use a semicolon, a comma with a coordinating conjunction (and, or, for, nor, but, yet, so), or a period (creating two sentences).

• I understand there must be rules; many forms of writing have rules.
• I understand there must be rules, and many forms of writing have rules.
• I understand there must be rules. Many forms of writing have rules.

There’s another type of run-on sentence. It results when you join two independent clauses with a conjunctive adverb and a comma. For example, this is a run-on sentence:

• Itemizing and attaching bills, therefore, constitutes prima facie evidence that medical charges were necessary and reasonable, however, there is still an issue of material fact to be considered.

The text contains two independent clauses:

• Itemizing and attaching bills, therefore, constitutes prima facie evidence that medical charges were necessary and reasonable.
• There is still an issue of material fact to be considered.

But they have been improperly joined—or spliced—with a comma and a conjunctive adverb: however. I do see this in legal writing—the example is from a brief filed in federal court—but it is, in fact, a run-on sentence and is improper in standard English.

As tempting as it may be, don’t treat conjunctive adverbs like coordinating conjunctions. If it helps, think of coordinating conjunctions as mere connectors and conjunctive adverbs as creators of transitions. In fact, they are often called “transition words.” Here’s a partial list of conjunctive adverbs:

To fix the “conjunctive adverb” run-on sentence, you have several options:

Use a semicolon:

• . . . charges were necessary and reasonable; however, there is still an issue . . .

Use a coordinating conjunction instead:

• . . . charges were necessary and reasonable, but there is still an issue . . .

Make two sentences:

• . . . charges were necessary and reasonable. However, there is still an issue . . .

(Yes, you can begin a sentence with however, despite Strunk & White.)

By the way, there’s a second conjunctive adverb in the original sentence, and it’s set off with commas and yet is correct:

• Itemizing and attaching bills, therefore, constitutes prima facie . . .

Using the conjunctive adverb in this way is correct because it doesn’t join two independent clauses. In short, “Itemizing and attaching bills” could not be a sentence by itself.

Learn to spot and fix run-on sentences, both the basic comma splice and the equally improper “conjunctive adverb” type.