What's the main idea?

It may be helpful to first explain what the main idea is not. It is not the information obtained during the introduction to the text when the title, headings, illustrations etc. are briefly considered, and linked to background knowledge, prior to reading. Although these text features are often useful in scaffolding readers towards finding the main idea, on their own, they are not enough. Readers need to explore the text at a deeper level in order to confirm or put aside any tentative thoughts about the main idea that the text introduction may prompt.

It is also important to note that the main idea is not simply what the text is about. To paraphrase Gerald Duffy (2003), "Charlotte's Web" is a story about a spider called Charlotte and a pig called Wilbur, but the main idea is more to do with the things that give life meaning: friendship, love, birth and death. The main idea then, is what the author wants readers to understand is important and valued in the text, i.e., across the whole text, not just within sections of it.

If you intend to use one of the Main Idea assessment resources available in the English bank and are not familiar with teaching the main idea comprehension strategy, it would be useful to read the "Teaching and learning" section of the resource prior to administering the task. The more you understand about the concept of main idea, the clearer you will be when you introduce the task to your students.

Finally, because the main idea is hardly ever explicitly stated by the author, and because readers can't get inside the author's head to find out exactly what they want readers to understand is important and valued in the text, readers can only ever make an informed guess about what the main idea is. Consequently, readers often disagree about the main idea. Any disagreement is best seen as a valuable opportunity for discussion.

How do you find the main idea?

When determining the main idea the reader uses text details, in conjunction with their prior knowledge, to think about what the main message of the text might be. As they read, they begin to tentatively group related details, constantly asking themselves where the author is placing emphasis or value. At various stages throughout the reading the reader may decide to reject very small groups of related details as not being particularly valued by the author. However, as they read on, gathering and grouping more details, they may reverse such a decision. Finally, the reader combines all the evidence, including their prior knowledge, and decides what is most important and valued in the text.

1 Identify the important information.

2 Group the important information.

3 Combine the groups to get the main idea.

What students and teachers might say:

Student:
"First I look for details, then I group them together to help me work out what the main idea is."

Teacher:
"Some of you think the main idea is 'you need to trust the people around you before you can try something new', and some of you think it's 'when you get out there and take risks, all sorts of doors open for you'. How do you think your background knowledge might be affecting what you think the main idea is?"

See	Effective Literacy Practice Y1–4 p. 133 Effective Literacy Practice Y5–8 p. 148 Duffy pp. 117–124 Harvey and Goudvis pp. 122–143 Miller pp. 141–156

Other resources with a focus on identifying the main idea: http://www.readingonline.org/articles/art_index.asp?HREF=/articles/brown/
This article reviews the literature on searching and extracting details and main ideas in paper-based informational texts. The article concludes with some suggestions for teacher professional development, some potential connections to searching digital texts, and some possible directions for raising overall reading comprehension.

Resources that explore the main idea  

It is important to remember that the reading strategies work together, and do not operate discretely. For examples of assessment resources with a particular focus on identifying the main idea, see the list below.