The SAT writing section includes 18 sentence-error-identification questions. The sentence-error-identification questions are designed to assess an individual's ability to identify grammatical mistakes within a sentence and/or mistakes with the way that a particular word or group of words is used within a sentence. Each of these questions will present the exam-taker with a sentence that has 4 parts of the sentence underlined; the individual will have to identify the underlined part that is incorrect or choose the "no error" option. For example, a question might present an individual with this sentence:

He was very (A) concerned that he had (B) performedpoorly on the (C) SAT, but he was (D) pleasant surprised when he received his scores. (E) No error

To answer, the individual would have to identify the choice that is incorrect within the sentence or choose (E) if the sentence is correct.

The answer for this example is (D), as the adjective pleasant should be replaced with the adverb pleasantly. (A), (B), and (C) are written correctly so they are not the correct choices for this particular example. (E) is also incorrect because there is a mistake within the sentence.

The mistake in this example is relatively obvious and many of the sentence-error-identification questions on the SAT writing section of the exam will have mistakes that are more difficult to identify. Each question will always require the exam-taker to identify similar mistakes in order to choose the correct answer.