How to identify Main Idea questions: Look for wording that refers to the general
or main point (aka the "Big Idea").
Some popular phrasings are:
What is the main point of the passage?
What argument is the author making?
The author is primarily concerned with advancing which of the following points?
What is the main idea?
Which of the following best summarizes the author’s argument?
Keep an eye out for words like main, general, summarize, and argument.
How to tackle them: If you follow the Five
Steps strategy, you should be able to locate the main idea easily. The only trick, then, is translating
your conception of the main idea into something that matches one of the answer
choices. Passages on the GMAT are relatively short. Therefore, the answer to
a main idea question cannot be too general or too specific. Main ideas tend
to be of medium focus.
If you're stuck, eliminate the options that are at the extremes of specificity: either very general or very detailed. This may leave you with one – probably, the right – answer; if it leaves you with more than one, you have still improved your chances of guessing correctly.
Here is an example question and its answer choices:
What is the main idea of the passage?
A) The Native Americans of Wichita have a long and rich cultural history.
B) Native Americans have traditions.
C) Chief Running Horse of the Wichita Native Americans enjoys the traditional New Year’s dance because he likes to watch his neighbor, Lone Tree, dance.
D) People have traditions.
E) The Native Americans of Wichita use dance in many of their traditions.
Now analyze the answer choices, looking for super-specific or super-general wording. Which choice is the most general? ...Most specific?
(D) People have traditions is extremely general. A book might
be able to cover such a broad topic, but a short passage can't address a wide enough variety of topics for this answer to make sense.
Americans have traditions is still too broad. Sure, Native Americans have traditions: but what traditions? If the answer choice says something so general and so obvious that there's no need to write an essay about it, it's probably wrong.
(C) Chief Running Horse of the Wichita Native Americans enjoys the traditional
New Year’s dance because he likes to watch his neighbor, Lone Tree, dance is far too specific. This idea can probably be found somewhere within the passage, but it's almost comically specific. The inclusion of this much detail and the lack of any generalized wording make this choice far too specific. It's an idea, but not the MAIN idea.
This leaves us with two answer choices: having eliminated the answer choices with overly specific and overly general wording, we know the answer is probably (A) or (E). Let's take a closer look at both:
(A) The Native Americans of Wichita have a long and rich cultural history.
(E) The Native Americans of Wichita use dance in many of their traditions.
Choice (A) sounds
very main idea-ish: note the balance of detailed (Native Americans of Wichita) and general (rich cultural history) description. Choice (E) is a bit less general, but could very well be the main idea of a different sort of passage. They both have a “medium” focus and are therefore good possible GMAT answers. Of course, to know which of the two is right you’d have to actually read the passage but by this process of elimination alone you have improved your chances of choosing the correct answer from 20% to 50%.