What You Need to Know about Assumption Questions in GMAT Critical Reasoning

When it comes to Critical Reasoning on the GMAT, one question that continues to frustrate people is the assumption question. Quite simply, the question is asking you which answer choice is required to support the conclusion that has been drawn in the passage. To successfully navigate these questions, you should use the Assumption Negation Technique, which requires a negation of the answer choice to determine whether or not it was actually required. More than that, though, the correct answer choice must be within the scope of the question. An answer choice that goes too far will not be the correct answer to the question.

As an example, think about a passage that deals with the Super Bowl. It’s very possible that the passage will discuss how good the Seahawks’ defense is, or how good Tom Brady is as a quarterback. The conclusion could then be something like how the Patriots will likely win (disclaimer: this was written before the Super Bowl). If a question was asked about what assumption is needed to reach the conclusion, the correct answer choice must be about Tom Brady or the Seahawks’ defense, given that’s what was discussed as evidence. If an answer choice discusses the catching ability of Rob Gronkowski or the Patriots’ (alleged) (systemic) pattern of cheating, then it is going outside the scope of the question and cannot be the correct selection.

It is important to note that strengthen and weaken questions may sometimes provide new information, so you should be on the lookout for things that weren’t written verbatim in the text. Nonetheless, for assumption questions, it’s easy to select an answer choice that provides new information but goes outside the scope of what was discussed. A choice that has no basis in the passage is usually a clear indicator of a trap answer.

Let’s look at an example to demonstrate scope in assumption questions:

It is a mistake to give post office employees individual discretion as to when to inspect or open suspicious packages. If individual employees are allowed to open “suspicious” packages without first following a strict protocol, it is only a matter of time before all packages will arrive having already been opened due to some postal employee’s idle curiosity.

The conclusion above is based on which of the following assumptions?

(A)   Postal service managers are the only people with the authority to open suspicious packages.

(B)   Suspicious packages are indistinguishable from all other kinds of packages.

(C)   The efficiency of the postal service will be greatly reduced if more packages are inspected.

(D)   There is currently no protocol in place for the inspection of suspicious packages.

(E)    Postal employees desire to open packages out of curiosity.

This question is asking about which assumption is required for the conclusion, which warns that all parcels will eventually be opened by overzealous mail carriers. While it’s somewhat understandable to be concerned about the privacy of your mail, the author’s fears may be unfounded (I’m more concerned about the NSA). The evidence provided in the passage is about when packages are allowed to be opened and verified. The passage mentions that only suspicious packages are allowed to be opened, but there are protocols in place that dictate when this verification can occur.

For assumption questions, the best strategy is to employ the Assumption Negation Technique and negate each answer choice to see if the conclusion falls down without the negated assumption. This approach is similar to the strategy of knocking down beams in a home to see which one was load-bearing. (Not something I’d recommend). If the conclusion falls down without this assumption, then it was absolutely required. If it changes nothing, then it was purely decorative and can be ignored.

Beginning with answer choice A, let’s negate them and see if the author’s paranoia is still defensible. The negation will be underlined to differentiate the negated form from the original assumption:

(A)   Postal service managers are not the only people with the authority to open suspicious packages.

If this were true, then there might be even more people who could open errant parcels. This makes the author’s argument more likely to be true, as seemingly random people could have authority to open packages. If nothing else, it certainly doesn’t lessen the chances of the author’s prediction coming to be, so this assumption is not required.

(B)   Suspicious packages are not indistinguishable from all other kinds of packages.

This double negation is saying that suspicious packages are easy to distinguish from other kinds of packages. If this were true, the employees would be able to tell which packages were suspicious, but they would nonetheless have the authority to open any package. Therefore, the fact that they can ascertain in most instances what constitutes a “suspicious” package would not necessarily stop them opening other packages. The passage is arguing that postal workers would open everything if given unilateral power, whether the package was deemed suspicious or not. This answer choice is probably the closest incorrect choice, but the scope alerts us to the superfluous nature of this assumption.

(C)   The efficiency of the postal service will not be greatly reduced if more packages are inspected.

This answer choice is discussing how the efficiency of the postal office (which many people think is an oxymoron) would not be affected by increasing the number of inspected packages. While this may quell the fears of some people who assume that more inspections would slow down the service, the author’s argument is primarily concerned with the privacy aspect of the inspections. This answer choice is thus out of scope, as the efficiency of the post office was (somehow) never in question.

(D)   There is currently no a protocol in place for the inspection of suspicious packages.

This answer choice, negated, indicates that there is already a protocol in place for suspicious packages. If this were true, it would actually strengthen the argument, as there would be no reason to give postal workers additional power to open packages. The system would indeed be working fine the way it is, and this argument only demonstrates the author’s point, it does not weaken it.

(E)    Postal employees do not desire to open packages out of curiosity.

This answer choice, by process of elimination, must be the correct choice. However, let’s confirm that it makes sense. If postal employees did not want to open packages out of (idle) curiosity, then the author’s entire argument would fall apart. Indeed, the entire argument relies on the fact that the postal employees will open every package they possibly can. If we could ensure that this was not the case (say with a hypnotic suggestion or some Borg nanoprobes), then the whole argument would become moot. Answer choice E is an assumption required by the conclusion, because without it, the argument falls apart.

On questions such as these, it’s entirely possible to get reeled in by an enticing answer choice. Remember to use the Assumption Negation Technique to verify whether an assumption is actually necessary or whether it just sounds important. The incorrect answer choices provided are designed to tempt you, so keep an eye on the evidence provided in the passage as well. If the answer sounds good, but isn’t based on the evidence provided, then much like the guy at my gym with halitosis, it is out of scope.

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Ron Awad is a GMAT instructor for Veritas Prep based in Montreal, bringing you weekly advice for success on your exam.  After graduating from McGill and receiving his MBA from Concordia, Ron started teaching GMAT prep and his Veritas Prep students have given him rave reviews ever since.