Introduction
Every SAT Reading and Writing passage exists for a reason — an author writes to argue a claim, explain a concept, illustrate a point with an example, qualify an idea, or critique a position. "Main purpose" questions ask you to name that reason accurately and precisely. These questions fall under the Craft and Structure domain, which accounts for roughly 28% of Reading and Writing operational questions. Identifying the main purpose of a text is one of the highest-yield skills in this domain because it requires you to read the passage as a whole, not just mine it for isolated details.
Note: This note covers main purpose questions only — the overarching rhetorical goal of the entire passage. Related skills like the function of a single sentence or phrase, common organizational structures, and purpose in literary passages are covered in their own separate notes.
Core Concept
The main purpose of a passage is the single, overarching communicative goal the author is trying to accomplish. On the SAT, the question stem usually reads:
- "The main purpose of the text is to…"
- "Which choice best describes the overall purpose of the passage?"
- "The author writes the passage primarily in order to…"
Your job is to match the correct purpose verb to what the author actually does across the whole passage — not just in one sentence. Purpose verbs are not interchangeable. Each one makes a specific claim about what the author is doing:
| Purpose Verb | What the Author Actually Does |
|---|---|
| Argue | Takes a stance and uses reasoning or evidence to defend it; a claim is being advanced |
| Explain | Breaks down how or why something works; neutral, informative tone; no strong position |
| Illustrate | Uses a specific example, anecdote, or case to make an abstract idea concrete |
| Qualify | Acknowledges limits, exceptions, or conditions that complicate an earlier or general claim |
| Critique | Identifies flaws, weaknesses, or errors in someone else's idea, method, or position |
| Describe | Gives details about the appearance, qualities, or nature of something without analyzing it |
| Compare | Examines similarities (and sometimes differences) between two subjects |
The key move: predict the purpose before you read the options. Ask yourself, "What is this author doing from the first sentence to the last?" Then match your prediction to the best available verb-plus-object pair in the answer choices.
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