Dispelling the Vagueness of GMAT Critical Reasoning Inference Questions

by on August 17th, 2012

Listen to a politician speaking, and you’ll hear a lot of platitudes and vague statements. Occasionally, a senator or congressman will make a statement about a specific number or an exact proposal; rarely, those statements will even be correct. But mostly, you’ll hear things like, “the hidden costs will total billions,” or “this program will have far-reaching negative impacts,” or “some have suggested that this proposed law will do nothing but enrich corporations.”

When you think about it, these claims make perfect sense. With a claim as vague as the ones above, it’s hard to be proven wrong or caught in a lie. For instance, “hidden costs” could refer to net costs, but it also could refer to gross costs even if the proposal actually netted a profit. “Billions” could refer to two billion, or it could refer to two hundred billion!

In other words, the vaguer the claim, the more likely it is to be true. And on GMAT Critical Reasoning Inference questions, which ask you to identify what must be true on the basis of a short statement, the vaguest answer is most likely to be correct.

It may seem contradictory that strong words like “must” are rarely the answer to a question that asks what “must be true.” But when you think about it, it makes sense. It’s very, very easy to conclude something is possible. It’s much harder to prove something is certain. For instance, it can be easy to prove that a type of thing might have a certain quality—for instance, you can prove that some swans are white by pointing to a single white swan. But proving thatall those things have that quality requires you to rule out every possible exception. Even if you show me 999 white swans, the 1,000th swan might turn out to be black!

You should always spend a few moments trying to predict the answer to an Inference question, even though it’s not always possible. And if the answer is too hard to predict, your next step should be to carefully check the answers for one that must be true. But sometimes, the computer adaptive test will give you a very high-difficulty problem, or you’ll be stuck between two answer choices, or you just won’t have time and need to guess strategically on a problem or two to beat the clock. And in those cases, picking the vaguest answer is one of the most reliable guessing strategies on the GMAT.

Consider the following GMAT practice problem. Without reading the text, can you figure out which answer is most likely correct? Then, go through the whole problem properly, and see why it’s a good fit. Good luck!


Randall: Many of the productions of my plays by amateur theater groups are poorly done, and such interpretations do not provide a true measure of my skills as a dramatist.

Which one of the following can be properly inferred from Randall’s statement?

(A) Some amateur theater groups’ productions of Randall’s plays provide a true measure of his skills as a dramatist.
(B) All amateur theater group productions of Randall’s plays that are not poorly done provide a true measure of his skills as a dramatist.
(C) All of the productions of Randall’s plays by amateur theater groups that do not provide a true measure of his skills as a dramatist are poorly done.
(D) If a production of a dramatist’s play is well done, then it provides a true measure of his or her skills as a dramatist.
(E) At least some amateur theatrical groups’ productions of Randall’s plays fail to provide a true measure of his skills as a dramatist.


Step 1: Identify the Question Type

The keywords “properly inferred” in the question stem are a sure sign of an Inference question.

Step 2: Untangle the Stimulus

Randall’s comments can be reduced to an if/then statement: If productions of his plays are poorly done, then they don’t provide a true measure of his skills as a dramatist. And many amateur theater groups perform his plays poorly.

Step 3: Predict the Answer

While we may not be able to predict what the correct answer choice will infer, we can be certain that it is a statement that must be true if we accept Randall’s statement as true.

Step 4: Evaluate the Choices

Since many amateur productions are poorly done, and no poorly done production provides a true measure of Randall’s skills, it must be true that at least some amateur groups’ productions do not provide a true measure of his skills, so (E) is correct. Don’t be afraid of (E) because it seems “obvious.” This is not a test maker trick—an “obvious” answer is one that must be true, so it works as a valid Inference.

(A) seriously distorts Randall’s statement. Just because some amateur productions don’t do him justice doesn’t mean that there are other productions that do. If the GMAT tells you that some marbles are red, you can’t automatically infer that some are not red.

(B) is another sort of distortion. Randall’s statement about certain poorly done productions in no way guarantees anything about productions that aren’t poorly done.

(C) is far too extreme. Randall does establish a correlation between poor production quality and failure to provide a true measure of his skills, but that correlation has only been established for a certain set of productions and can’t be extended to all productions.

(D) attempts to extract a broad principle from Randall’s statement, but his statement is too particular to allow this kind of extrapolation.

The correct answer is (E).


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