Conclusions are Key in Critical Reasoning

Critical reasoning questions on the GMAT tend to follow the same structure over and over again. This means that they can be answered the same way over and over again (like the movie Groundhog Day, but with words!). The first step is to determine which type of question you’re dealing with, which is why identifying the category is the first step towards successfully answering the question. The four major categories can be remembered with the mnemonic SWIM:

 

 

  1. Strengthening the conclusion
  2. Weakening the conclusion
  3. Inferring based on the conclusion
  4. Method of reasoning used

As you can easily tell from the categories above, the conclusion usually plays a pivotal role in correctly answering the question at hand. Thus, identifying the author’s point is a necessary step that cannot be circumvented. In particular, let’s focus in on strengthening the argument or weakening the argument, two sides of the same coin that can often be solved the exact same way (you may need to insert the word “not” somewhere)

Within the context of a strengthening or weakening question, the three steps to correctly solving the question are always the same (and very similar to casing a joint for a heist)

  1. Identify the conclusion
  2. Evaluate the premise(s)
  3. Find the gap between the conclusion and the premise.

Again, the conclusion is the key to everything. If you correctly identify the conclusion, you’re on the right path to success. If you misidentify the conclusion, you will likely fall into a clever trap laid out for you. Let’s look at an example:

Nate: Recently a craze has developed for home juicers, $300 machines that separate the pulp of the fruits and vegetables from the juice they contain. Outrageous claims are being made about the benefits of these devices: Drinking the juice they produce is said to help one lose weight or acquire a clear complexion, to aid in digestion, and even to prevent cancer. But there is no indication that juice separated from the pulp of the fruit or vegetable has any properties that it does not have when unseparated. Save your money, if you want carrot juice, eat a carrot.

Which of the following, if true, most calls into question Nate’s argument?

(A)  Most people find it much easier to consume a given quantity of nutrients in liquid form than to eat solid foods containing the same quantity of the same nutrients.

(B)  Drinking juice from home juicers is less healthy than is eating fruits and vegetables because such juice does not contain the fiber that is eaten if one consumes the entire fruit or vegetable.

(C)  To most people who would be tempted to buy a home juicer, $300 would not be a major expense.

(D)  Nate was a member of a panel that extensively evaluated early prototypes of home juicers

(E)  Vitamin pills that supposedly contain nutrients available elsewhere only in fruits and vegetables often contain a form of those compounds that cannot be as easily metabolized as the varieties found in fruit and vegetables.

After quickly identifying the type of question (calls into question = weaken), the next step on the road to success is to identify the conclusion. Looking over Nate’s soliloquy, the majority of it is context as to how the juicing craze came about, the positive aspects of juicers (the unexpected plot twist when the juicer was betrayed by Cobra) and the negative aspects of juicers. The conclusion, summed up in a succinct manner at the end is simply “Save your money, if you want carrot juice, eat a carrot.”

The trap that many people fall for here is that Nate’s argument is based primarily on monetary issues. Yes the juicer separates the juice from the pulp, but it’s not worth the money! (C’mon you could take that money and buy ¾ of an Apple share). If you focus in on the money aspect, you probably want to pick answer choice C, because it indicates that the money won’t be a big concern for prospective clients. However, this is a trap based on the phrasing of the conclusion.

The conclusion could have just as easily read “Don’t be a fool, if you want carrot juice, eat a carrot”. This conveys the exact same message, but answer choice C would now have to be something akin to “Most people who would buy this juicer have IQs above 114½”. The call for saving your money is simply used for emphasis; it has little bearing on the actual issue, which is that you get the same nutrients from solid foods as you would from consuming only the juice.

For strengthening/weakening questions, the third step of minding the gap between the premise and the conclusion is necessary to determine which answer choice to select. In this question, the premise is talking about the nutrients of one form versus the other, and the conclusion states that there’s no reason to ever want the juice instead of the solid. What’s the gap? Maybe there’s another reason we would want the juice! Perhaps it tastes better, or your teeth aren’t as solid as they used to be and juice is preferable to trying to bite into an apple (or perhaps you’re trying to cross a border and fruits are illegal but the juice is fine).

Upon rereading the answer choices, A is exactly what you want. The others all fall down in various ways.

(A)  Most people find it much easier to consume a given quantity of nutrients in liquid form than to eat solid foods containing the same quantity of the same nutrients.

Perfect. This gives us a valid reason to want to drink the juice.

(B)  Drinking juice from home juicers is less healthy than is eating fruits and vegetables because such juice does not contain the fiber that is eaten if one consumes the entire fruit or vegetable.

Tempting, but this strengthens the argument instead of weakening it. 180 °.

(C)  To most people who would be tempted to buy a home juicer, $300 would not be a major expense.

Trap answer based on financial considerations.

(D)  Nate was a member of a panel that extensively evaluated early prototypes of home juicers

Again, wouldn’t this make Nate an expert on the subject? Strengthener and 180 °.

(E)  Vitamin pills that supposedly contain nutrients available elsewhere only in fruits and vegetables often contain a form of those compounds that cannot be as easily metabolized as the varieties found in fruit and vegetables.

New topic. Why are we introducing vitamin pills here? Out of scope.

The correct answer is (A). 

On these types of critical reasoning questions, correctly identifying the conclusion is paramount to correctly answering the question. Hijacking the conclusion will result in an answer choice that seems correct, but doesn’t address the underlying point the author is making. And since strengthening and weakening questions make up the majority of Critical Reasoning questions on the GMAT, the only conclusion you should come to is to practice these questions regularly.

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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.

One Response

  1. Moni says:

    wow ! Good & detailed article!!!

    I had a query about choice D, Ron.

    I was between choice A & D… rejected choice A for the word “easier”.
    No idea in which direction i was thinking.

    I chose D as i thought since Nate was an evaluator , she must be biased to reject the juicer right away..
    Can you please tell me what was wrong with my way of thinking?

    Thanks!

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