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How To Tackle Main Idea Questions on Reading Comprehension

by , Sep 9, 2010

glasses-on-book-excerptWere continuing our recent RC theme and I have another student question for you: whats the best way to tackle Main Idea or Primary Purpose questions?

Reading the passage

In order to answer Main Idea or Primary Purpose questions correctly, we need to understand the overall Point of the passage, and in order to find The Point, we need to know how to read the passage in general. Luckily, we already have articles for both of those tasks!

First, read How to Read a Reading Comp Passage. Then, read How to Find the Point in a Reading Comp Passage. Once youve read those two articles (and practiced the material a bit), come back here and continue with this article.

Note: if you are struggling to read and comprehend effectively and efficiently, you may also want to review this article: How to Improve your Reading Skills for RC.

Recognizing the question

Before we can answer a Main Idea question, we have to recognize that we have a Main Idea-type question in the first place! Below is a list of sample language that allows us to recognize a Main Idea question. Words in quotes are taken from The Official Guide for GMAT Review 12th Edition (OG12), The Official Guide for GMAT Review 11th Edition (OG11), or GMATPrep. (Note: this list does not represent a comprehensive list of all of the ways in which the test might word a Main Idea question, though the first two on the list represent the majority of the Main Idea-type questions).

  • what is the primary purpose?
  • the passage or the author is primarily concerned with what?
  • which answer best summarizes the central idea?
  • which answer states the main idea?
  • what is the central purpose?

A question can also be limited to only part of the passage: you might be asked, for example, to find the primary purpose of the second paragraph. If the question limits the scope to something more narrow than the entire passage, be very careful as you review the answers. There will almost certainly be a trap answer that will talk about the entire passage, or include information that is not in the specified paragraph.

Answering the question

First, we need to know what they want from us on Main Idea-type questions. They want us, of course, to have understood the overall Point (or The Point of a particular paragraph, if one is specified). Theres more to it than that, though. They typically also want us to know how to abstract The Point: to talk about it in more abstract, general language. Almost all answer choices for Main Idea questions are made more generic and will not necessarily include specific details or names from the passage.

For example, RC question #1 in OG12 asks for the primary purpose and this is the wording of the correct answer:

present a concern about the possible consequences of pursuing a particular business strategy

See how vague that language is? The passage itself talks about the concept of ecoefficiency. The passage defines the term in the first sentence; the second sentence names two specific men and presents their argument: ecoefficiency is laudable but [it] could actually worsen environmental stresses in the future. The second sentence gives us The Point of the passage. Most of the rest of the passage provides detail to support that Point (various potential negative consequences) and to discuss what the men think should happen instead.

Its important, then, to rephrase The Point in our own words before we look at the answers. The answers almost certainly arent going to contain specific language from the passage, so we really want to understand The Point in our own words without worrying about retaining the specific words used in the passage. We also want to keep a pretty tight eye on what The Point does cover and what is not actually discussed or covered in the passage.

In the case of the first passage in OG12, it tells us that the men dont completely hate ecoefficiency (they call it laudable) but they think it could end up having the opposite of the intended effect: it could ultimately have negative instead of positive consequences. Ecoefficiency is a business strategy and the men have a concern about the possible consequences of using it.

Thats how we might explain why the right answer is right. What about the wrong answers? Why are they wrong and, equally importantly, why are they tempting? One wrong answer says:

explain why a particular business strategy has been less successful than was once anticipated

This choice is tempting because the men are saying that this business strategy that is supposed to help the environment might end up harming it! That could certainly be described as less successful. So why is it wrong? This choice says that the strategy has already been less successful we already know that ecoefficiency isnt as successful as we thought it would be. Right? Hmm. Thats not what the passage says. The men claim that it could actually worsen environmental stresses in the future. This is an example of a choice that people might pick if they read a bit too much into the passage: theyre not being careful enough about what the passage does say and what it does not say.

What about this choice:

propose an alternative to a particular business strategy that has inadvertently caused ecological damage

Whats tempting about this one? Well, the two men do propose something of an alternative in the second-to-last sentence of the paragraph. Okay. What about the second part of the choice: a strategy that has inadvertently (already) caused ecological damage. Does the passage provide support for the idea that ecoefficiency has already caused ecological damage? You already know the answer to that; look at our discussion of the last answer choice! This is an example of a wrong answer that starts off okay (propose an alternative to a particular business strategy) but then goes too far at the end, with a tacked-on detail that wasnt actually in the passage. If its going to be the right answer, then it has to be 100% right, even the details!


  1. Know how to read the passage efficiently and effectively, and know how to pick out The Point.
  2. Know how to recognize immediately which specific type of question you were given. If its a Main Idea question, make sure you can articulate The Point in your own words before you look at the answers.
  3. Know what to expect from correct and incorrect answers on Main Idea questions.

Copyright note: the text excerpted above from The Official Guide for GMAT Review 12th Edition, 11th Edition, or GMATPrep is copyright GMAC (the Graduate Management Admissions Council). The short excerpts are quoted under fair-use statutes for scholarly or journalistic work; use of these excerpts does not imply endorsement of this article by GMAC.