Source: Comma Splice 1 Answer Key, English Composition II (Purdue University)
Difficulty: Beginner | Prerequisites: Basic understanding of what a sentence is (subject + verb = complete thought).
Comma splices are one of the most common sentence-level errors in English composition, and one of the first grammar topics tested in introductory writing courses. If you can spot an independent clause (a group of words that could stand alone as a sentence), you can learn to spot a comma splice. This topic sits at the foundation of sentence mechanics: fixing comma splices forces you to understand how clauses connect, which feeds directly into stronger, more varied sentence structure. If you have been away from the course for a few weeks, start here before moving on to run-on sentences or semicolon usage.
A comma splice happens when you join two complete sentences with nothing but a comma. Fix it by adding a coordinating conjunction (and, but, so), swapping the comma for a semicolon, splitting into two sentences, or turning one clause into a dependent clause. If you can cover the second half and the first half still works as a sentence, you are probably looking at a splice.
Comma splice
A sentence error in which two independent clauses are joined by a comma alone, with no coordinating conjunction or other appropriate punctuation.
In simple terms, this means you stuck two full sentences together with just a comma, and that is not enough glue.
Independent clause
A group of words containing a subject and a verb that expresses a complete thought and can stand on its own as a sentence.
Think of it as any chunk of words that could end with a full stop and still make sense.
Coordinating conjunction
One of seven words (for, and, nor, but, or, yet, so) used to connect two independent clauses when preceded by a comma. The mnemonic is FANBOYS.
Think of it as the bridge word that, together with a comma, legally joins two complete sentences.
Conjunctive adverb
A transitional word (however, consequently, therefore, moreover, then, also) that connects ideas between independent clauses. When used between two independent clauses, it requires a semicolon before it and a comma after it, not just a comma.
In simple terms, this means words like "however" and "consequently" look like they should work the same as "and" or "but," but they do not. They need a semicolon.
Subordinating conjunction
A word (although, because, if, when, while, since, unless) that turns an independent clause into a dependent clause, making one clause rely on the other for its meaning.
Think of it as the word that demotes a full sentence to a sentence fragment, so it has to lean on the other clause.
Run-on sentence
The broader category of sentence errors where two independent clauses are joined incorrectly. A comma splice is a specific type of run-on. A fused sentence (no punctuation at all between the clauses) is the other type.
In simple terms, this means "run-on" is the umbrella term, and "comma splice" is one flavour of run-on.
Look at the comma in the sentence. Cover everything after the comma (and any word immediately following it, like "however" or "then").
Ask: does what remains before the comma form a complete sentence on its own?
Now look at what comes after the comma. Does that also form a complete sentence on its own?
If both sides are independent clauses and the only thing joining them is a comma, you have a comma splice.
Example from the source: "My apartment is too small, I have no room for my treadmill and exercise bike."
Left side: "My apartment is too small" = complete sentence.
Right side: "I have no room for my treadmill and exercise bike" = complete sentence.
Joined only by a comma = comma splice.
A comma between two independent clauses is fine if a coordinating conjunction (FANBOYS) follows the comma.
"My son Geoffrey plays drums in band called Talent Scam, and he likes to surf at Playalinda Beach." = Correct. The comma is followed by the coordinating conjunction "and."
A comma is also fine when one side of it is not an independent clause.
"Although I understand the definition, comma splices still confuse me." = Correct. "Although I understand the definition" is a dependent clause (introduced by the subordinating conjunction "although"), so no splice exists.
A comma used to separate items in a list within a single clause is not a splice.
"I like to read suspense novels, email my friends, and play cards with my daughter." = Correct. The commas separate items in a series, not independent clauses.
Words like "however," "consequently," "therefore," "then," and "moreover" feel like connectors, but they are not coordinating conjunctions. Using them after a comma between two independent clauses produces a comma splice.
"I'm exhausted, however, I will go to school anyway." = Comma splice.
"Tom opened his freezer, then he noticed that two cans of beer had exploded." = Comma splice.
"I hiked for five hours yesterday, consequently I am too tired to go hiking again today." = Comma splice.
To fix these, use a semicolon before the conjunctive adverb and a comma after it: "I'm exhausted; however, I will go to school anyway."
Add a coordinating conjunction (FANBOYS) after the comma.
"My apartment is too small, so I have no room for my treadmill."
Replace the comma with a semicolon.
"My apartment is too small; I have no room for my treadmill."
Split into two separate sentences.
"My apartment is too small. I have no room for my treadmill."
Make one clause dependent using a subordinating conjunction.
"Because my apartment is too small, I have no room for my treadmill."
"However" works the same as "but." It does not. "But" is a coordinating conjunction and can follow a comma between clauses. "However" is a conjunctive adverb and needs a semicolon before it. The same applies to "then," "consequently," "therefore," and "moreover."
Any sentence with a comma in it might be a comma splice. Only sentences where the comma sits between two independent clauses (with no coordinating conjunction) are splices. Commas in lists, after introductory phrases, and after dependent clauses are all fine.
Long sentences are more likely to be comma splices. Length is irrelevant. A short sentence can be a splice ("It rained, we left"), and a long sentence with proper conjunctions or dependent clauses is correct.
You can fix a comma splice by just removing the comma. Removing the comma without adding anything else creates a fused sentence (another type of run-on), which is equally wrong.
⚠️ Conjunctive adverbs (however, then, consequently) between independent clauses are the most commonly tested comma splice pattern. The exam will almost certainly include at least one.
⚠️ Expect sentences with "although," "because," or "if" as distractors. These introduce dependent clauses and are correct, which is exactly why they appear alongside real splices to test whether you know the difference.
⚠️ List sentences ("I like A, B, and C") and compound sentences with FANBOYS ("X, and Y") are standard correct-sentence distractors. Know why they are not splices.
⚠️ Being able to identify and fix comma splices matters beyond exams. In any professional or academic writing, comma splices are flagged as basic errors that undermine your credibility with the reader.
Answer True or False. Check your answers at the bottom of this section.
A comma splice occurs when two independent clauses are joined only by a comma. (T/F)
The word "however" is a coordinating conjunction. (T/F)
"Although she was tired, she kept studying" is a comma splice. (T/F)
You can fix a comma splice by replacing the comma with a semicolon. (T/F)
FANBOYS stands for: for, and, nor, but, or, yet, so. (T/F)
Answers: 1. True 2. False (it is a conjunctive adverb) 3. False ("although" creates a dependent clause) 4. True 5. True
Q: Is the following a comma splice? "Some people value money and material possessions, others value love and family."
A: Yes. Both sides of the comma are independent clauses with no coordinating conjunction. Fix options: add "but" after the comma, replace the comma with a semicolon, or split into two sentences.
Q: Why is "I'm exhausted, however, I will go to school anyway" a comma splice?
A: "However" is a conjunctive adverb, not a coordinating conjunction. It cannot join two independent clauses with just a comma. The correct version uses a semicolon: "I'm exhausted; however, I will go to school anyway."
Q: Identify and fix the error: "It's means 'it is' or 'it has,' its' is always incorrect."
A: This is a comma splice. Two independent clauses are joined only by a comma. Fix: "It's means 'it is' or 'it has'; its' is always incorrect." (Or use a full stop and two sentences.)
Q: Why is "Although I understand the definition, comma splices still confuse me" not a comma splice?
A: The clause before the comma ("Although I understand the definition") is a dependent clause, introduced by the subordinating conjunction "although." A comma splice requires two independent clauses. Only one independent clause is present here.
Q: Name the four methods for correcting a comma splice.
A: (1) Add a coordinating conjunction after the comma. (2) Replace the comma with a semicolon. (3) Split into two sentences with a full stop. (4) Make one clause dependent by adding a subordinating conjunction.
Q: "A comma splice occurs when two complete sentences are joined only by a comma, I need to remember that rule." Is this a comma splice? Explain the irony.
A: Yes, it is a comma splice. Two independent clauses are connected only by a comma. The irony is that the sentence defining a comma splice is itself a comma splice.
This connects to run-on sentences because a comma splice is a specific type of run-on. Once you understand splices, fused sentences (run-ons with no punctuation at all) become easier to spot.
This connects to semicolon usage because the semicolon is one of the primary tools for fixing a comma splice, and understanding when to use a semicolon between clauses starts here.
This connects to sentence variety and style because learning to fix comma splices pushes you toward using subordination, coordination, and varied sentence structures, all of which strengthen your writing in composition courses and beyond.
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