Central ideas in informational texts: determining the central idea of a passage (stated as a full sentence, not a topic word), distinguishing the central idea from supporting details, writing an objective summary, and tracing how the author develops the central idea across paragraphs on a LEAP English I or II informational passage.

What this skill is asking

The central idea of an informational text is the main point the whole passage develops, and stating it precisely is one of the most common LEAP English I and II informational tasks. It is the nonfiction cousin of theme: where a literary passage has a theme, an informational passage has a central idea, and both must be stated as a full sentence rather than a topic word. You will see it as a multiple-choice question ("which best states the central idea"), as an objective-summary task, and as an evidence-based item that pairs the central idea with a supporting detail. It is also the backbone of the Research Simulation Task, where you synthesize the central ideas of several sources into your own essay. This page covers stating the central idea, distinguishing it from supporting details, writing an objective summary, and tracing how the author develops the idea across paragraphs. The transferable skill is reading nonfiction for the point it is making, not just the topic it covers.

Central idea versus topic versus detail

The biggest central-idea error is confusing the main point with the topic or with one detail.

The test for a central idea is the same as for a theme: it must be a full sentence that makes a point. "Pollution" is a topic; "individual habits matter less to pollution than industrial regulation" is a central idea. If your answer is one or two words, it is a topic, so turn it into a claim about the subject. A passage can have a central idea plus several sub-ideas in different paragraphs; the central idea is the one the whole passage builds toward. Louisiana standard RI.9-10.2 asks you to determine a central idea and analyze its development, and to provide an objective summary, so the test wants both the idea and how it is built.

Tracing development and summarizing

The central idea is usually built across the passage, not stated once.

Objectivity is what trips students on summary questions: a summary reports what the text says, not what you think about it, so phrases like "this is a good argument" do not belong. The skill connects to author's purpose (why the author makes this point), to text evidence and inference (the details that support it), and most of all to the Research Simulation Task, where synthesizing the central ideas of multiple sources into one essay is the whole task. Reading for the central idea is the foundation of all informational reading on LEAP.

Working a central-idea item

Try this

Q1. What is the difference between a topic, a central idea, and a supporting detail? [Recall]

• Cue. A topic is the subject in a word; a central idea is the full-sentence main point about that topic; a supporting detail is a fact or example that develops the central idea.

Q2. A passage argues, with examples from three cities, that public libraries boost local economies. State the central idea and name the kind of support. [Short explanation]

• Cue. Central idea: public libraries strengthen local economies. The support is examples or evidence (the three cities), which develop the point. On a summary question, you would state that idea and the three-city support in your own words, without opinion.