Quick Answer
A comma splice occurs when two independent clauses are joined by only a comma without a conjunction. On the Digital SAT, this error is frequently tested within the 'Boundaries' question type in the Reading and Writing section. Students must identify these mistakes to ensure sentences are punctuated according to Standard English Conventions.
A comma splice is a grammatical error where two independent clauses—groups of words that can stand alone as complete sentences—are linked using only a comma. To be grammatically correct, these clauses must be separated by a period, a semicolon, or a comma paired with a coordinating conjunction.
Question: The spacecraft entered the Martian atmosphere at high speeds, its heat shield protected the delicate instruments inside. A) speeds, its B) speeds; its C) speeds its D) speeds, although its Solution: Choice B is correct. The original sentence is a comma splice because 'The spacecraft entered the Martian atmosphere at high speeds' and 'its heat shield protected the delicate instruments inside' are both independent clauses. A semicolon is required to fix the error.
Mistake 1: Misidentifying conjunctive adverbs like 'however' or 'therefore' as coordinating conjunctions, leading students to use only a comma before them.
Mistake 2: Failing to recognize the second subject in a long sentence, causing the student to treat the second independent clause as a dependent phrase.
Mistake 3: Over-relying on 'ear-testing' where a natural pause in speech makes a comma seem correct, even if the grammatical structure requires a semicolon.
Students targeting 750+ should know that the SAT often complicates comma splice questions by inserting a long parenthetical phrase or a non-essential clause immediately before or after the splice point. Always identify the core subject-verb pairs of the main clauses to ensure you aren't being distracted by 'filler' text that makes the splice harder to spot.
Coordinating Conjunction
A coordinating conjunction is a word used to connect words, phrases, or independent clauses on the Digital SAT. These seven words—for, and, nor, but, or, yet, so—typically appear in the Reading and Writing section under Standard English Conventions questions, where they are essential for fixing run-on sentences and comma splices.
Fragment
A fragment is a group of words that lacks an independent clause, failing to express a complete thought. On the Digital SAT, fragments are frequently tested within the Reading and Writing section under 'Boundaries' questions. Typically, these appear 2–4 times per exam, requiring students to identify and correct incomplete sentence structures.
Independent Clause
An independent clause is a grammatical unit that contains a subject and a verb and expresses a complete thought. On the Digital SAT, this concept is frequently tested in the Reading and Writing section, particularly within Standard English Conventions questions. Students must often distinguish between independent and dependent clauses to avoid punctuation errors like comma splices.
Run-On Sentence
A run-on sentence occurs when two independent clauses are fused without proper punctuation or conjunctions. On the Digital SAT, these errors appear frequently within the Reading and Writing section. Mastering this concept is crucial, as approximately 3 to 5 "Boundaries" questions typically test your ability to fix these errors.
Semicolon
A semicolon is a punctuation mark used on the Digital SAT to link two independent clauses without a coordinating conjunction. Appearing frequently in the Reading and Writing section under 'Standard English Conventions,' it typically tests a student's ability to identify complete sentences and avoid comma splices or run-on sentences in 'Boundaries' questions.
A comma splice on the SAT is a punctuation error where two independent clauses are incorrectly joined by a comma alone. This concept is a major component of the Reading and Writing section's 'Boundaries' questions. It tests a student's ability to distinguish between complete sentences and fragments, requiring the use of stronger punctuation or conjunctions to connect full ideas correctly.
To identify a comma splice, read the text on either side of a comma to see if both parts can stand alone as complete sentences. If both the preceding and following word groups contain a subject and a verb and express a finished thought, a comma alone is grammatically incorrect. On the SAT, look for these 'double-sentence' structures in the provided answer choices.
A comma splice is technically a specific type of run-on sentence. While a general run-on sentence might have no punctuation at all between two independent clauses, a comma splice attempts to use a comma to bridge them. Both are considered 'boundary' errors on the SAT because they fail to properly separate two distinct, independent thoughts with the required grammatical weight.
The Digital SAT typically includes approximately 3 to 5 questions per test that specifically target sentence boundaries, including comma splices. These questions are consistently found in the Standard English Conventions portion of the Reading and Writing modules. Because they appear regularly, mastering the rules for fixing comma splices is a highly effective way to improve your overall verbal score.
