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Determining Central/Main Ideas

Nonfiction/Informational Texts RI 10.2

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Adapted from Petty’s PowerPoint

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Standard for Reading Informational Text

2. Determine a central idea of a text and analyze its development over the course of the text, including its relationship to supporting ideas; provide an objective summary of the text.

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Determining Central/Main Ideas in Nonfiction

  • Nonfiction works develop central ideas through the use of supporting details.
  • A central idea is a key point the author wants to make.
  • All the details in the text develop and support the central idea by:
    • Proving it
    • Explaining it
    • Illustrating it
    • Giving further details

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Determining Central Ideas

  • In most cases, the author directly states the central idea near the beginning of the text.
  • In other cases, the central idea is implied by the points the author makes.
  • We readers can infer the central idea by determining what point all of the details combine to support.

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The Role of the Paragraph

  • Each paragraph in nonfiction develops its own main idea.
  • This main idea is used to support the main idea of the whole text.
  • The main idea of a paragraph is often stated in a topic sentence.
  • The topic sentence is then supported by reasons, examples, and other details in the paragraph.

All details in each paragraph, as well as each paragraph itself, serve the larger purpose of developing the central idea of the whole work.

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Central Idea: Our town should build a skate park for skateboarders.

Topic Sentence:

A park would keep skateboarders out of the street.

Topic Sentence:

Skateboarders would no longer damage public property, such as curbs.

Topic Sentence:

A park would inspire skateboarders to take pride in our town.

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Central Idea

  • How a text’s central idea is developed is directly related to the author’s purpose, or reason for writing.
  • Example Purposes: To inform, to persuade, to entertain

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Rock climbing is dangerous.

Purpose

  • To inform

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  • To persuade

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  • To entertain

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Angle

  • Include facts about accidents.

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  • Add arguments about the need for safety.

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  • Include comical details about a rock climbing experience.

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In summary:

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  • Central ideas are the main ideas identified and developed in nonfiction.
  • Usually, central ideas are directly stated by the author at the beginning of a text.
  • Each paragraph in a nonfiction text contains a central idea with supporting details, and each paragraph serves to support the central idea of the work as a whole.
  • An author’s purpose for writing determines how a central idea will be developed.
  • Central ideas will be supported through details in the text, and it is our job as readers to figure out what the idea is. It’s the “so what?” of our reading.

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