Shift the Burden on Inference Questions

Shift the Burden on Inference Questions
An answer choice worded so that it's presumed to be true unless disproven is often the correct answer (Photograph by Getty Images)
Photograph by Getty Images

This tip for improving your GMAT score was provided by David Newland at Veritas Prep.

The correct answer to an inference question is the answer that must be true based on the facts given in the stimulus. This is an imposing standard for an answer choice to try to meet.

Yet there are times when the way the answer choice is worded actually shifts the balance so that the answer is presumed to be true unless it is disproven. It is in your best interests to look closely at such an answer choice, because there is a good chance that it is the correct answer.

Take the following: “Atmospheric waves might not be the only factor that effects the formation of hurricanes.” This answer choice effectively shifts the burden so that the only way “might not be the only factor” would be untrue is if it can be shown that atmospheric waves ARE the only factor that effects the formation of hurricanes.

This is a complete reversal. Instead of presuming that the answer could be false and looking for information that would make it true, you can presume that the answer is true and only eliminate if definite information shows it is false.

Take the following two statements: “I will win the lottery.” “I might win the lottery.” The first statement takes an incredibly high level of proof. Basically the lottery has to “rigged” for you to know for sure that you will win. But for the second statement to be true, you just need to have an lottery ticket. Sure, the odds are against your winning, but until you actually lose, you still might win. The second statement would be the correct answer if the stimulus merely indicates that you hold a lottery ticket.

A word like “might” is a great way to shift the burden, but even without it, an answer choice can still shift the burden. Let’s reword our previous example about hurricanes: “Atmospheric waves cannot be the only factor that affects the formation of hurricanes.” This statement is no longer just a possibility; it is a definite statement and seems to be harder to prove. In fact, all that is needed to make this the correct answer is one example in the stimulus of a hurricane’s formation being influenced by something other than the atmospheric waves. “Cannot be the only” is another great way to shift the burden.

Try the following question from the Veritas Prep Critical Reasoning book. Be sure to look for the answer choice that shifts the burden.

In a recent study, a group of subjects had their normal daily caloric intake increased by 25 percent. This increase was entirely in the form of alcohol. Another group of similar subjects had alcohol replace nonalcoholic sources of 25 percent of their normal daily caloric intake. All subjects gained body fat over the course of study, and the amount of body fat gained was the same for both groups.

Which one of following is most strongly supported by the information above?

(A) Alcohol is metabolized more quickly by the body than are other food and drinks.
(B) In [the] general population, alcohol is the primary cause of gains in body fat.
(C) An increased amount of body fat does not necessarily imply a weight gain.
(D) Body-fat gain is not dependent solely on the number of calories one consumes.
(E) The proportion of calories from alcohol in a diet is more significant for body fat gain than are the total calories from alcohol.

Did you see which one shifts the burden? Answer Choice D. The statement, “Body fat gain is not dependent solely on the number of calories one consumes,” requires only that some other factor also affects body-fat gain. The stimulus gives you that factor in the form of alcohol consumption. The stimulus also indicates that one group increased its calorie intake and the other group did not, yet both groups gained the same amount of body fat. Clearly calories are not the only factor in body fat gain, and Choice D is correct.

When you find an answer choice that “shifts the burden” on an inference question, pay close attention, because that answer choice just might be correct.

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