ROn Point: Become an Assumption Expert on the GMAT

On the GMAT, the information provided to you will be factual, but it won’t necessarily be helpful. Once you have made peace with this unfortunate reality, the goal soon becomes to transform factual information into useful information in order to solve the question. This type of analysis is prevalent in the quantitative section of the exam, but also shows up in the verbal section. Statements provided will often contain implicit information that you must convert into explicit information. In essence, you need to get a handle on the assumptions being made.

There is an old saying about assumptions. (Paraphrased brilliantly in the Fresh Prince of Bel-Air, the coach warned that the “ump” will “tion” you.) As is almost always the case with assumption questions, correctly identifying which of them are critical can be confusing, intimidating and awkwardly phrased. With that kind of pedigree, who wouldn’t love to see such a question on their GMAT:

In North America there has been an explosion of public interest in, and enjoyment of, opera over the last three decades. The evidence of this explosion is that of the 70 or so professional opera companies currently active in North America, 45 were founded over the course of the last 30 years.

The reasoning above assumes which one of the following?

(A)   All of the 70 professional opera companies are commercially viable options.
(B)   There were fewer than 45 professional opera companies that had been active 30 years ago and that ceased operations during the last 30 years.
(C)   There has not been a corresponding increase in the number of professional companies devoted to other performing arts.
(D)   The size of the average audience at performances by professional opera companies has increased over the past three decades.
(E)    The 45 most recently founded opera companies were all established as a result of enthusiasm on the part of a potential audience.

Without a sound strategy to tackle these questions, many of these choices look very tempting. The first answer indicates that opera makes money, assuredly keeping them afloat for future performances. The last answer choice virtually paraphrases the question, so that can’t be wrong, can it? I’ve heard every single answer choice on this question proposed by students over the last year. Of course, if Highlander taught us anything, it’s that there can only be one. (Highlanders 2-4 subsequently taught us that they should have stopped at one)

How do we separate the wheat from the chaff here? We have to figure out which assumptions are necessary for the conclusion to hold, and which cleverly strengthen the argument without being necessary. To accomplish this, we need to determine whether the conclusion could hold without the assumption. If it can, the stated assumption wasn’t that important. If it cannot, then that assumption was the key to the whole process. This method is known as the Assumption Negation Technique (or ANT, and like any ant, it is deceptively strong).

(A)   NOT All of the 70 professional opera companies are commercially viable options.

The negation of all is “not all”, not “none”. This implies that there could be 67 commercially viable companies, two that are losing money and one is non-profit. If the vast majority of the companies are thriving, this still strengthens the conclusion. Either way, this strengthens the conclusion, implying that the assumption is not necessary to the conclusion.

(B)   There were fewer MORE than 45 professional opera companies that had been active 30 years ago and that ceased operations during the last 30 years.

This is saying that there were, say, 100 professional opera companies in 1983 (or whenever 30 years ago was) and that 75 of them closed in the last three decades. So if 45 new companies opened up but 75 closed, there are fewer companies than there used to be, and opera is actually on the decline versus 1983. This assumption is necessary to keep the conclusion logical, as the absence of this particular assumption destroys the conclusion that opera is getting more popular.

(C)   There has not been a corresponding increase in the number of professional companies devoted to other performing arts.

Does the number of professional ballet or symphony companies have anything to do with opera? A subtle attempt to conflate somewhat similar artistic endeavors, but nonetheless irrelevant to the question at hand.

(D)   The size of the average audience at performances by professional opera companies has NOT increased over the past three decades.

Similarly to choice A, the negation of increased is not increased, allowing for the number to stay stable or decrease slightly. Combining this with more companies and performances than before, there could be more enthusiasm without the average audience size needing to increase at all. Not a necessary assumption, although a tempting choice due to the obvious strengthening of the stated conclusion.

(E)    The 45 most recently founded opera companies were NOT all established as a result of enthusiasm on the part of a potential audience.

This is the same logic as choice A. Perhaps 2 companies were established as tax shelters to funnel money into the Cayman Islands and another was set up as a bet between eccentric millionaires attempting to circumvent the globe by hot air balloon in 80 days. They do not all need to be established as a result of audience enthusiasm, so the assumption is nice to have, but not crucial to the point being made.

The correct answer is (B).

Using the Assumption Negation Technique, it becomes easier to determine which assumptions are necessary and which strengthen the conclusion without being key to the argument at hand. In this particular example, the correct answer doesn’t necessarily prove the author’s conclusion on its own, but it does remove a potentially catastrophic flaw, therefore strengthening the conclusion. It is not the strongest conclusion of the bunch, but it is the only one that is indispensable for the author’s point to hold.  In fact, objectively this is at best the third strongest strengthener of the gang, but it is the most essential. (much like comparing the heart, biceps and calf muscles…)

In assumption Critical Reasoning questions, the goal is always to find the assumption that knocks the argument down if it is removed. The challenge is that is frequently a bland or uninteresting choice that doesn’t draw the eye. In practice, this means you’re often down to choosing between A and B, while the correct answer is C. In eliminating possible answer choices, always be sure that the assumption is not necessary for the conclusion to hold, rather than looking for which strengthens the conclusion the most. You can be sure that if you’re choosing between the two answer choices that most strengthen an assumption question, you’re likely choosing between trap answer 1 and trap answer 2 (like a really bad episode of the Bachelor).

To avoid this undesired fate, it is helpful to have a concerted strategy to tackle any assumption question, and ANT is your best approach to avoid Critical Reasoning pitfalls. ANT is a very strong technique (and currently my second favorite ant after aunt Jemima) because assumption answer choices are virtually impossible to predict ahead of time. The use of ANT helps alert you to its necessity and avoid tempting superfluous choices.

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Ron Awad is a GMAT instructor for Veritas Prep based in Montreal, bringing you occasional tips and tricks 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.

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