How to solve SAT Central Ideas and Details questions

Central Ideas and Details questions ask you to state the main point of a short passage or to find a specific detail the passage gives. They belong to the Information and Ideas domain, which makes up about 26% of the Reading and Writing section, roughly 12 to 14 questions shared among three skills. Expect a few Central Ideas and Details questions on each test. The passages run from about 25 to 150 words and cover science, history, social studies, the humanities, and literature, including poems and excerpts from novels and plays.

What the questions look like

Most of these questions use one of three stems.

• Main idea. "Which choice best states the main idea of the text?" The passage is often a short summary of a study or an argument, and the answer is the sentence that sums up all of it.
• Detail. "According to the text, what is true about the researchers' findings?" or "Based on the text, why did the town council reverse its decision?" The answer is a paraphrase of something the passage says outright.
• What happens. "Which choice best describes what happens in the text?" This version usually comes with a literary excerpt, and you summarize the events or the shift in a character's thinking.

Step-by-step method

1. Read the question first so you know whether you are looking for the main idea or one detail.
2. Read the entire passage. Many passages open with an older view and then turn on a word like "however," "but," or "recently." The main idea usually comes after that turn.
3. Before you look at the choices, state the main idea in your own words in one sentence. Name the subject and what the passage claims about it.
4. For a detail question, find the exact sentence that answers it. You should be able to point to it.
5. Compare each choice to your summary or to that sentence. Cross out any choice that covers only part of the passage, goes beyond it, or contradicts it.
6. Before you commit, check every part of the remaining choice against the text. One unsupported word is enough to make a choice wrong.

Worked example

For decades, archaeologists assumed that the large stone grinding tools found at an ancient farming settlement were used only to process wild grains. Recently, a team led by archaeologist Hana Ruiz examined microscopic residue trapped in the tools' surfaces. Along with traces of barley, the team found starch grains from acorns and from several root vegetables that do not grow near the site. Ruiz argues that the residents relied on a wider range of plant foods than researchers once believed and that some of these foods probably came from trade or seasonal travel.

Which choice best states the main idea of the text?

A) Stone grinding tools were more common at early farming settlements than archaeologists once thought.
B) Residue analysis suggests that the settlement's residents ate a broader variety of plants than earlier researchers assumed.
C) The residents of the settlement depended on barley more than on any other food.
D) Archaeologists no longer study grinding tools because residue analysis has replaced that work.

Answer: B. The passage moves from an old assumption, that the tools processed only wild grains, to new evidence of acorns and distant root vegetables, to Ruiz's conclusion that the residents' diet was wider than expected. Choice B covers all of that.

Choice A reuses the words "grinding tools" and "once thought," but the passage never discusses how common the tools were. Choice C picks out barley, which is only one food in the list, and the text never says it was the main one. Choice D invents a claim. Ruiz's team is still studying the tools.

Here is a second example, this time with a literary passage.

Teodora had practiced the speech for a week, reciting it to the bathroom mirror, to the cat, and to the bus window on her way to school. When the principal finally called her name, she walked to the microphone, unfolded her notes, and found that her hands were perfectly steady. Only after she sat down again, to applause she barely heard, did she notice that her knees would not stop shaking.

Which choice best describes what happens in the text?

A) A student forgets her speech and has to improvise in front of her school.
B) A student gives a speech calmly and feels her nerves only after it is over.
C) A student refuses to give a speech until the principal insists.
D) A student practices a speech but decides it is not ready to deliver.

Answer: B. Her hands are "perfectly steady" at the microphone, and her knees start shaking only "after she sat down again." Nothing in the passage says she forgot anything, refused, or backed out, so A, C, and D each add events the text does not contain.

Common traps

• The true but narrow choice. A choice can repeat a real detail and still fail as a main idea because it leaves out most of the passage. Choice C in the first example is this trap. Ask whether the choice could work as a summary of the whole text.
• The old view. When a passage starts with what people used to believe, a choice that restates that belief is wrong for a main idea question. The answer reflects where the passage ends up.
• Overreach. Words like "proves," "always," "only," and "all" are red flags unless the passage uses language that strong. The correct answer is usually as cautious as the passage.
• Recycled wording. Wrong choices often reuse key words from the passage so they look familiar. Check what the choice claims, not which words it shares with the text.
• Outside knowledge. A choice might be true in the real world but absent from the passage. If you cannot point to support in the text, eliminate it.

Quick check

Before you click, run three tests on your answer.

• Could it serve as a one-sentence summary of the whole passage?
• Can you point to the sentence or sentences that support each part of it?
• Does it reflect the passage's final position rather than the view the passage argues against?