Students often struggle determining the main idea of a text. They need direct and explicit instruction on the skill. But before you start teaching main idea, you may need to backfill and clarify that students know some other skills first.
Topic v. Topic Sentence
Before students can grasp implicit main idea, make sure they can find explicit topic sentences. Provide short passages (even single paragraphs) and ask students to identify which is the topic sentence and which sentences include supporting and specific details.
Here is a single paragraph about the benefits of a hand dryer, where the topic sentence is the first sentence. But not all paragraphs start with a topic sentence. The placement can be different and requires students to practice identifying the topic sentence. (Here is a website where students can practice finding the topic sentence.)
Define Main Idea
Eventually explain the difference between a text’s topic and its main idea. The topic can be stated in 1-2 words, whereas main idea is a 4-8 word statement. A well-written main-idea sentence does more than announce the topic. It identifies the specific angle or facet of the topic being addressed. The topic is within the main-idea sentence.
Utilize newspaper headlines
Newspaper headlines are a great source for main-idea examples. They are mini-sentences that succinctly express the angle or perspective of the article.
To demonstrate this to students, first reveal several different articles all on the same topic but with different main ideas (e.g., 2012 Super Bowl examples). Point out how the topic (i.e., the Super Bowl) is within each of the main-idea sentences.
Another approach is to have students match main-idea sentences to a passage. Provide 2-4 articles on the same topic, again with each having a different main idea. Remove the original headlines and ask students to match articles to their appropriate main-idea headlines.
If that is going well, students are ready to move to the more difficult task of inferring main idea on their own. Provide them with a single, short newspaper article and ask them to guess the headline. Remind them to first determine the topic and then to include it in a single 4-8 word sentence that summarizes the entire article. Compare their headlines to the original one that accompanied the published article.
TIP: Rather than using a newspaper article, consider utilizing the informational text passages that come within your Weekly Reader, Time for Kids, or other subscriptions.
When first teaching main idea, start with informational text. It’s typically easier to determine what a nonfiction passage is “all about.” Whereas figuring out the author’s message in literature can be a little more abstract and thus challenging.
Determine main idea of literature
When you’re ready to delve into literature, start with short stories or individual chapters. These shorter texts are easier than asking students to infer the main idea of an entire novel.
After reading a chapter, assign students to write a single-sentence main-idea chapter title that encompasses the gist of the chapter. (TIP: If you do this for every chapter, when you’re done, students will have an excellent summary of the entire text.)
Consider revealing main-idea titles in songs and book titles. For primary, use picture books to demonstrate the difference between topic and main idea. Then show students how to write main-idea titles in response to picture books they read.
Apply to internet searching
Being able to whittle down a text to a single-sentence summary is more than just a standardized test skill. This is a real-world skill. Think of an online search. When searching under broad terms or topics (1-2 words), you receive a multitude of results. However, typing in a specific angle or facet of the big topic (4-8 words) will narrow the pool, providing results that are more focused and relevant.