Quick Answer
The em dash is a versatile punctuation mark on the Digital SAT used primarily to set off nonessential information or provide emphasis. Frequently appearing in the Reading and Writing section under Standard English Conventions, it functions similarly to commas or parentheses when used in pairs to isolate parenthetical phrases.
An em dash (—) is a long punctuation mark used to indicate a break in thought, set off an appositive, or introduce a list or summary. Grammatically, a pair of em dashes must enclose nonrestrictive elements, while a single em dash can signal a sudden shift or provide a colon-like introduction.
Question: The red panda—a small arboreal mammal native to the eastern Himalayas [ ] is more closely related to raccoons than to giant pandas. A) , B) ; C) — D) : Solution: The correct answer is (C). Because the nonessential phrase 'a small arboreal mammal native to the eastern Himalayas' begins with an em dash, it must conclude with an em dash to maintain grammatical consistency.
Mistake 1: Mixing punctuation by starting a nonessential phrase with a comma but trying to end it with an em dash, which is always incorrect on the SAT.
Mistake 2: Overusing the dash for emphasis without checking if the surrounding sentence structure actually requires a break or a nonessential boundary.
Mistake 3: Confusing the em dash with the shorter hyphen, which is used for compound words rather than grammatical sentence structure.
Students targeting 750+ should know that while the em dash can often function like a colon to introduce a list or explanation, it is unique because it can also be used in pairs. If you see a single dash near the end of a sentence, check if it is introducing a concluding thought; if you see one in the middle, look for its 'partner' dash to ensure a nonessential phrase is properly balanced.
Appositive
An appositive is a noun or noun phrase that renames another noun right beside it. On the Digital SAT, these frequently appear in the Standard English Conventions questions of the Reading and Writing section. Mastery of appositives is essential, as they typically appear in approximately 10-15% of punctuation-based questions.
Colon
The colon is a punctuation mark used on the Digital SAT primarily to introduce lists, explanations, or emphasis. In the Reading and Writing section, 'Boundaries' questions frequently test this mark. A colon must follow a complete independent clause, a specific rule that distinguishes it from other punctuation marks in standard English conventions.
Comma Splice
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.
Nonrestrictive Clause
A nonrestrictive clause is a descriptive element in the Digital SAT Reading and Writing section that provides non-essential information about a noun. These clauses, frequently tested in Standard English Conventions questions, appear in approximately 15-20% of grammar-based items and must be set off by symmetrical punctuation such as commas, dashes, or parentheses.
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.
An em dash is a punctuation mark used on the Digital SAT to signal a break in a sentence or to set off nonessential information. It appears primarily in the Reading and Writing section under Standard English Conventions. It is longer than a hyphen and serves a structural purpose, often acting as a more emphatic alternative to commas or parentheses when isolating descriptive phrases.
To use an em dash correctly, you must determine if it is being used singly or in a pair. Use a pair of em dashes to surround a nonessential clause that adds extra detail to a sentence. Use a single em dash to introduce a concluding explanation, a list, or a sudden shift in thought, provided the preceding clause is independent.
An em dash and a colon can both introduce a list or an explanation at the end of an independent clause. However, the em dash is generally considered more informal or emphatic. On the SAT, they are rarely both correct options for the same function unless the em dash is being used as part of a pair to set off an internal phrase.
While the exact number varies by test form, you will typically encounter approximately two to four questions involving em dashes in the Reading and Writing section. These questions usually focus on 'Standard English Conventions,' asking you to maintain consistency in punctuation or to correctly identify where a nonessential phrase begins and ends within a complex sentence structure.
