Comma Splices on the SAT
The Easy Points You Keep Missing
Master sentence structure, punctuation, and clarity with repeatable rules.
Guard the Sentence Core
Identify the subject and verb, then make sure punctuation does not split them or add extra ideas.
- Find the subject + verb first. That is the sentence core.
- Only add commas around extra information, never inside the core.
- Re-read the sentence without the modifier to test clarity.
Why Comma Splices Matters on the SAT
What most students don't realize is that certain SAT Reading and Writing questions follow the exact same pattern every time. Comma splices are one of those patterns. Once you learn to recognize them, you can answer these questions quickly, and that kind of speed adds up. If comma splice questions appear two, three, or even four times on your test, that's potentially 2–4 points you pick up just by knowing one rule.
This post zeroes in on comma splices, cases where two complete sentences are joined with nothing but a comma. That's a specific type of boundary error, and it's the one the SAT tests most often. If you're looking for run-on sentences with no punctuation at all, or how to choose between coordination and subordination when combining clauses, those are covered in their own dedicated posts. Here, we're staying focused on the comma-only join, the one mistake that shows up again and again.
The best part? The rule itself is simple. You've probably been making comma splices in your own writing without even knowing it. This post will teach you exactly what a comma splice is, why the SAT cares about it, and how to fix it every time. Let's turn this into the easiest points on your test.
What Is a Comma Splice?
A comma splice happens when you use a comma, and only a comma, to connect two independent clauses. That's it. That's the whole error.
Before we go further, let's make sure you're solid on one term. An independent clause is a group of words that has a subject and a verb and can stand on its own as a complete sentence. For example:
- The library was nearly empty., That's an independent clause.
- Only a few students remained., That's also an independent clause.
Now smash them together with just a comma:
The library was nearly empty, only a few students remained.
That's a comma splice. The comma isn't strong enough to hold two complete sentences together on its own. Think of it like trying to connect two train cars with a piece of string, it technically touches both sides, but it can't bear the weight.
How to Fix a Comma Splice
There are four reliable ways to fix a comma splice. Every correct answer on the SAT will use one of these:
- Period: Split them into two sentences.
The library was nearly empty. Only a few students remained. - Semicolon: Join them with a semicolon, the sentences must be closely
related.
The library was nearly empty; only a few students remained. - Comma + coordinating conjunction (FANBOYS): Add one of the seven
coordinating conjunctions, for, and, nor, but, or, yet, so.
The library was nearly empty, and only a few students remained. - Restructure: Turn one clause into a dependent clause or phrase so it can no
longer stand alone.
Because the library was nearly empty, only a few students remained.
The "However" Trap
This is the misconception that catches the most students: words like "however," "therefore," "moreover," and "consequently" do NOT work like coordinating conjunctions. These are called conjunctive adverbs, and putting a comma before them still creates a comma splice.
Wrong: The experiment failed, however the team remained optimistic.
Right: The experiment failed; however, the team remained optimistic.
Notice the fix: a semicolon before "however" and a comma after it. The SAT loves testing this distinction. If you see "however" or "therefore" in the answer choices, check the punctuation around it carefully.
SAT Strategy: Spotting Comma Splices Fast
On the SAT Reading and Writing section, here's your game plan:
- Step 1: Look at both sides of the comma in the underlined portion. Can each side stand alone as a sentence? If yes, you're looking at a potential comma splice.
- Step 2: Check whether there's a coordinating conjunction (FANBOYS) right after the comma. If there isn't one, the original is wrong, eliminate it.
- Step 3: Scan the answer choices for a proper fix: a period, a semicolon, a comma + conjunction, or a restructured sentence.
That's it. Three steps, and you've got your answer. With practice, this becomes nearly automatic.
Practice Comma Splices with SAT-Style Questions
Try these SAT-style questions. Each one tests your ability to spot and fix a comma splice. They start straightforward and get slightly trickier, just like the real test.
Which choice best corrects the underlined portion?
Which choice most effectively combines these ideas?
Which choice best joins these clauses?
Which choice most effectively connects these ideas while emphasizing the result of the revision process?
Key Takeaways for Comma Splices
- A comma splice is two independent clauses joined by only a comma. It is always wrong on the SAT.
- Four fixes: period, semicolon, comma + FANBOYS conjunction, or restructure the sentence so one clause becomes dependent.
- Don't fall for the "however" trap: Conjunctive adverbs like "however," "therefore," and "consequently" need a semicolon before them, not a comma. The SAT tests this distinction frequently.
- Use the two-side test: Can each side of the comma stand alone as a sentence? If yes and there's no FANBOYS conjunction, it's a comma splice, eliminate that choice.
Conclusion: The Core Rule for Comma Splices
Comma splices are one of the most predictable and learnable patterns on the SAT Reading and Writing section. The rule is straightforward, the fixes are consistent, and the test uses this question type repeatedly. Invest a little practice now, work through these questions again if any felt uncertain, and you'll recognize comma splices instantly on test day. These are the points you don't leave on the table.
Remember: Two complete thoughts need more than a comma. Check both sides, look for a conjunction, and pick the fix. That's your formula for free points.
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