Being able to identify main ideas and supporting details in texts is an important reading skill that is worth mastering. It will greatly improve your English reading comprehension. It will also help you write better essays, and get the score you want on English exams.

How to Identify the Main Idea and supporting details
Ask yourself, “what is the general idea that the author wants to express?” Read the full title of the text, and skim for the thesis statement in the introductory paragraph. A thesis statement is a declaration of the central point or argument, and is often (but not always) found at or near the end of the first paragraph.
The supporting details are concepts and ideas that promote or reinforce the main idea. They are often explicitly stated in the form of topic sentences. You can usually find the topic sentences at the beginning of paragraphs. If you can’t identify the topic sentences, look for key words and ideas that are repeated.
Dates, statistics, and examples are not considered essential parts of a text. Think of it this way. If you are preparing a pasta dish, you can choose to add any number of different sauces. The pasta is essential.
How to Practice
The chart above is a standard format for mapping the different types of ideas in a text. Get in the habit of writing down the main idea and supporting ideas when you are reading.
Lets do a reading practice together, and see how identifying the main idea and supporting ideas helps us analyze the text.
An Example of a C2 Level Text and Reading Comprehension Questions
The following is an excerpt from Modern World History (Allosso and Williford)
1.) Skim read the text, and identify the thesis statement.
2.) What other ideas support or expand upon the main idea? Write them under the main idea as supporting details.
3.) Read and select your answer to the two multiple questions below the text.
When we think of the Cold War between the United States and the Soviet Union, we typically imagine the thousands of nuclear missiles each nation pointed toward the other and of a clash of ideologies as communism and capitalism battled for world supremacy. A defining element of the Cold War was that it did not become a hot war. Neither the U.S. not the U.S.S.R. launched attacks on the territories of the other. Instead, the superpowers supported or intervened in the conflicts of nations in their spheres of influence. To a great extent, the Cold War was a struggle by each superpower to extend its sphere of influence and block the other from doing the same. The Soviets and the Americans justified their actions in a variety of ways. Creating a buffer-zone to protect the homeland. Defending like-minded governments against a different political or economic philosophy. One side said it was protecting the world from the threat of totalitarian communist imperialism and the other said it was protecting the world from imperialist capitalism. Interestingly, both accused their antagonist of being an empire.
World War Two in Europe was nearly over when Stalin, Roosevelt, and Churchill met at Yalta in February 1945, but the war in the Pacific was still ongoing. This fact weighed heavily on the British and Americans, who were hoping for Soviet help in defeating Japan. Stalin had signed a Non-Aggression Pact with the Japanese in 1941, which both sides maintained during the conflict; at Yalta, he pledged to declare war on Japan three months after the German surrender. In exchange, Roosevelt and Churchill essentially agreed to the Soviet military occupation of Eastern Europe. It would turn out that this would be the beginning of the Cold War between the U.S. and the Soviet Union, which would not be fought directly between the two superpowers, but rather through proxy wars in the developing world over most of the next five decades.
World War II in Europe was nearly over when Stalin, Roosevelt, and Churchill met at Yalta in February 1945, but the war in the Pacific was still unresolved. Stalin had signed a Non-Aggression Pact with Japan in 1941 which both sides had maintained during the conflict. Roosevelt and Churchill urged Stalin to join them in defeating Germany’s final Axis partner. Stalin agreed to declare war on Japan three months after the German surrender. In exchange, Roosevelt and Churchill essentially agreed to accept the Soviet military occupation of eastern Europe.
Comprehension Questions
Question 1- Which of the sentences below best expresses the essential information in the following sentence?
World War Two in Europe was nearly over when Stalin, Roosevelt, and Churchill met at Yalta in February 1945, but the war in the Pacific was still ongoing. This fact weighed heavily on the British and Americans, who were hoping for Soviet help in defeating Japan. Stalin had signed a Non-Aggression Pact with the Japanese in 1941, which both sides maintained during the conflict; at Yalta, he pledged to declare war on Japan three months after the German surrender. In exchange, Roosevelt and Churchill essentially agreed to the Soviet military occupation of Eastern Europe. It would turn out that this would be the beginning of the Cold War between the U.S. and the Soviet Union, which would not be fought directly between the two superpowers, but rather through proxy wars in the developing world over most of the next five decades.
A.) Stalin made an agreement with Japan to attack Germany within three months.
B.) In 1941, Stalin and Japan made a Non-Aggression Pact.
C.) While Stalin upheld his Non-Aggression Pact with Japan throughout the conflict, he agreed to declare war on them after the German surrender.
D.) Stalin initially honored his agreement not to attack Japan, but changed his mind three months after the German surrender, and declared war.
Question 2 – What it the purpose of this reference to the proxy wars? Why are proxy wars relevant?
World War Two in Europe was nearly over when Stalin, Roosevelt, and Churchill met at Yalta in February 1945, but the war in the Pacific was still ongoing. This fact weighed heavily on the British and Americans, who were hoping for Soviet help in defeating Japan. Stalin had signed a Non-Aggression Pact with the Japanese in 1941, which both sides maintained during the conflict; at Yalta, he pledged to declare war on Japan three months after the German surrender. In exchange, Roosevelt and Churchill essentially agreed to the Soviet military occupation of Eastern Europe. It would turn out that this would be the beginning of the Cold War between the U.S. and the Soviet Union, which would not be fought directly between the two superpowers, but rather through proxy wars in the developing world over most of the next five decades.
A.) The U.S. and the Soviet Union were at war.
B.) The U.S. and the Soviet Union were engaged in a hot war.
C.) The U.S. and the Soviet Union were not engaged in a hot war.
D.) The Cold War between U.S. and the Soviet Union was fought indirectly.
Question 3 – Select the 3 most important points.
A When we think of the Cold War between the United States and the Soviet Union, we typically imagine the thousands of nuclear missiles each nation pointed toward the other and of a clash of ideologies as communism and capitalism battled for world supremacy. B A defining element of the Cold War was that it did not become a hot war. Neither the U.S. not the U.S.S.R. launched attacks on the territories of the other. C Instead, the superpowers supported or intervened in the conflicts of nations in their spheres of influence. D To a great extent, the Cold War was a struggle by each superpower to extend its sphere of influence and block the other from doing the same. E The Soviets and the Americans justified their actions in a variety of ways. Creating a buffer-zone to protect the homeland. Defending like-minded governments against a different political or economic philosophy. One side said it was protecting the world from the threat of totalitarian communist imperialism and the other said it was protecting the world from imperialist capitalism. F Interestingly, both accused their antagonist of being an empire.
List the three most important points, by their letters.
Answers and Logic
Question 1 is an example of Sentence Simplification Question. These types of questions determine if you can identify the most important information, and if you understand the relationship between ideas.
In this case, the correct answer is C. We know this because we have identified the main idea. The main idea, or thesis of the essay is that “a defining element of the Cold War was that it did not become a hot war”.
If we failed to identify the main idea, we can use a process of elimination. We can eliminate A and D, because they are not what the text says. And we can eliminate B, because while it is true, it is not essential information. (Remember, dates are usually sauce, not pasta.)
Question 2 is an example of a Rhetorical Purpose Question. The rhetorical purpose is the reason the author included the information. The answer isn’t stated in the text, and unless you know the main idea that the writer wants to get across, it would be difficult to guess.
Thankfully, you know that the fundamental point that the author wants to make is that “a defining element of the Cold War was that it did not become a hot war”. And so we know that the answer is C.
Question 3 is an example of a prose summary questions. These questions are about identifying the most important information in a text. Incidentally, in the TEOFL exam, there are 3 correct answers out of 6, and you get 2 points if you select all 3 of the correct ones!
Here, the answer is B, C, D.
Again, having identified the main idea helps us answer the question. We know that the thesis, or main idea is the crux of the essay, and we know that this is B. C and D support this central idea best. They are the water and heat that make the pasta possible.
Keep practicing!
The best way to master this basic reading comprehension skill is to practice. So find something to read, use a chart to identify what the author most wants to say, and what details support it.

