Critical reasoning on the GMAT requires you to evaluate the author’s conclusion and select the answer choice that best answers the given question. While there are four broad categories of questions, the two most common types of questions are the ones that ask the student to either strengthen or weaken the conclusion provided. In actuality, strengthen and weaken questions are two sides of the same coin (possibly Two Face’s trick coin) and together account for roughly ¾ of the critical reasoning questions on the exam. With stats like these, it’s important to be comfortable with these questions!
First, we must identify the author’s conclusion. This usually is done by trying to understand the author’s main point. Likely, the main idea being pushed will be the conclusion. You can usually recognize a conclusion if it contains a call for action or begins with conclusion language. This conclusion language is usually a telltale word like “Thus” or “Therefore” (or my favorite: “In conclusion”). The conclusion is likely based on the premises or evidence in the passage, so continuously asking yourself “why?” will usually help identify the conclusion. If there is an answer to the question “why” in the text, you might have the conclusion in your sights.
Once you have identified the conclusion of the passage, the next important element to look for is the supporting evidence in the passage, particularly in terms of gaps that can be exploited. Very frequently the gap between the evidence and the conclusion will yield the crux of the question. If you think the Miami Heat will win the NBA championship because Miss Cleo told you, there might be a gap to exploit…
If you’ve properly identified the conclusion and the evidence, the inevitable gap in logic between the two will form the basis of your prediction of the answer. Predicting the answer is a key step in correctly solving strengthen/weaken questions, as the erroneous answer choices are specifically chosen to tempt you into considering them as potentially worthy candidates. If you go in with an open mind, you might end up picking something that sounds reasonable but is irrelevant to the situation at hand (think of late night TV shopping: Yes I do need a knife that cuts through a shoe).
Once you feel comfortable in this approach, let’s try and apply it to a real GMAT question:
The retail price of decaffeinated coffee is considerably higher than that of regular coffee. However, the process by which coffee beans are decaffeinated is fairly simple and not very costly. Therefore, the price difference cannot be accounted for by the greater cost of providing decaffeinated coffee to the consumer.
The argument relies on assuming which one of the following?
(A) Processing regular coffee costs more than processing decaffeinated coffee
(B) Price differences between products can generally be accounted for by such factors as supply and demand, not by differences in production costs
(C) There is little competition among companies that process decaffeinated coffee.
(D) Retail coffee-sellers do not expect that consumers are content to pay more for decaffeinated coffee than for regular coffee.
(E) The beans used for producing decaffeinated coffee do not cost much more before processing than the beans used for producing regular coffee.
If we apply the strategy above, the conclusion is clearly the last sentence of the passage (Therefore kind of gave it away). The conclusion states that the price difference cannot come from the cost of providing decaffeinated coffee. What is the evidence provided? Only that the process of decaffeination is simple and cheap. What could be an alternative explanation for the price difference? Anything else! For example, if the material provided cost more money or the process can only be performed by Tibetan monks on the third Saturday of the month. Any given reason could be valid to increase the price (sort of like cartels).
Let’s look through the answers to see which of these could cause legitimate increases in cost:
A) Processing regular coffee costs more than processing decaffeinated coffee.
This choice is actually out of scope. The answer choice purports that regular coffee is more expensive than decaf. If we negate it, it tells you that processing regular coffee costs LESS than processing decaf. But we already know processing decaf is inexpensive, so this answer choice doesn’t help anything. Whether it’s true or false, it doesn’t give any more insight into producing decaf coffee.
B) Price differences between products can generally be accounted for by such factors as supply and demand, not by differences in production costs.
This is a very tempting answer because many people know it to be true. However, it is incorrect because it is tangential to the point we’re trying to prove. Were this not true, would it change anything to the cost of processing coffee beans? Not at all. This answer choice is true in the vast majority of situations; however it is irrelevant to the author’s conclusion and therefore cannot be the correct answer.
C) There is little competition among companies that process decaffeinated coffee.
Similar to the choice above, but much less tempting. What does this have to do with anything? There’s competition. If anything, that should drive the costs down, not up. This answer choice is also irrelevant to the conclusion, and if it were relevant, it would be pointing in the wrong direction.
D) Retail coffee-sellers do not expect that consumers are content to pay more for decaffeinated coffee than for regular coffee.
This is a 180°. The answer choice suggests that people do not want to pay more for decaf, so why would the decaf coffee be so much more expensive? If anything, it should be cheaper. This answer choice is also incorrect.
E) The beans used for producing decaffeinated coffee do not cost much more before processing than the beans used for producing regular coffee.
This is the correct answer. My prediction was to ensure nothing else was driving up the price of coffee. If the beans were much more expensive, then the cost of providing decaffeinated coffee could be very high even though the process is inexpensive. In economic terms, the labor was cheap but the capital was expensive. This answer choice would strengthen the argument tremendously, and without it, the argument has a sizeable flaw that could be exploited.
On strengthen and weaken questions, it’s very easy to get confused as to what the question is actually asking you, especially after 3 hours of brain taxing concentration. Actively predicting what the answer choice should look like will help you avoid tempting trap answer choices. When fatigue starts to creep in during the verbal section, keeping a proactive approach to critical reasoning questions will help you select the correct answer and keep your concentration level high. This is especially important if the only coffee beans you’ll get on the GMAT will be in critical reasoning questions.
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.