Need-to-Know Terminology

For GMAT Critical Reasoning, you won’t need to know the technical terminology of formal logic, except for a few basic terms. Here are the ones you should know before you proceed any further.

• ARGUMENT: The process of reasoning—from premises to conclusion.



• PREMISE: A proposition helping to support the argument’s conclusion; premises form the basis on which reasoning proceeds; premises are often signaled with words and phrases such as since, because, and given that.



• ASSUMPTION: Something taken for granted to be true in the argument; strictly speaking, assumptions are actually unstated, assumed premises.



• CONCLUSION: A proposition derived by inference from the premises of an argument. Conclusions are typically signaled by words and phrases such as hence, as a result, consequently, therefore, and it follows that.



• INFERENCE: The process of deriving, from assumed premises, either the strict logical conclusion or a conclusion that is to some degree probable.

Critical Reasoning—Your 6-Step Game Plan

The first task is to learn the six basic steps for handling a GMAT Critical Reasoning question. You’ll apply these steps to the following sample question:

Among customers of breakfast restaurants, more order fresh fruit for breakfast than any other menu item. However, a recent healthresearch report indicates that eating eggs does not pose as significant a health risk as previously thought. In response to this report, operators of breakfast restaurants should increase the number of eggs but decrease the amount of fresh fruit they order from their suppliers.

Which of the following, if true, would be the best reason to reject the recommendation made in the argument above?

1. Eating eggs still poses a substantial health risk, especially for males over age fifty.
2. Most fresh fruits are available only seasonally, whereas eggs are available any time of the year.
3. Alternatives to breakfast egg dishes, such as pancakes and cereals, are growing in popularity at breakfast restaurants.
4. Many customers of breakfast restaurants who order eggs also order fresh fruit.
5. Compared to fresh fruits, pre-prepared fruit juices are growing in popularity among people who dine at breakfast restaurants.

Step 1: Read the question “stem” (the actual question or prompt that follows the passage). Reading the question stem first will tell you what you should think about as you read the passage. Be sure you understand the specific task that the question is asking you to perform.

Step 2: Read the passage and identify its key elements. Identify the argument’s conclusion (if any) and its premises. If the passage contains a conclusion (most Critical Reasoning passages do), try to follow the argument’s line of reasoning from premise(s) to conclusion. To help yourself along, try reading the passage again, starting with the conclusion. (Critical Reasoning passages are brief, so a second reading won’t take much time.)

Step 3: Try to formulate your own answer to the question.

Step 4: Read the five answer choices, looking for one that provides something similar to one of the “best” answers you’ve formulated. But, don’t assume that your home-grown “best” answer will look exactly the way you imagined it. Just look for a choice that conveys the same general idea. Also, keep an open mind to a possible “best” answer that hasn’t yet occurred to you.

Step 5: If you’re still not sure what the best answer choice is, eliminate whichever ones you can. Eliminate choices that make no sense to you, that don’t seem directly relevant to the argument, or that accomplish just the opposite of what the question asks for.

Step 6: Compare the quality of the remaining (viable) answer choices. Try to determine which is qualitatively better than the others. Don’t try to make ultra-fine semantic distinctions, parse words, or second-guess the test-makers. The qualitative difference between the best and any runner-up choice will be clear enough—if your thinking is straight enough.

Now let’s walk through the sample question about breakfast restaurants, using this 6-step approach.

Step 1: This question stem tells you quite a bit about the passage as well as what to look for in a viable answer choice. The stem essentially asks you to recognize how the argument can be weakened. Since it refers to the “argument above,” you know that the passage will contain at least one premise (information that you should assume is factual) as well as a conclusion, which, in this case, will be in the form of a “recommendation.”

Step 2: The passage’s last sentence expresses the argument’s conclusion, while the first two sentences indicate the premises on which the conclusion is based. So, what’s the line of reasoning here; in other words, what’s the logical connection between the premises and the recommendation? Apparently, the passage’s author thinks that breakfast-restaurant customers now know that its okay to eat eggs, so a significant number will begin ordering eggs instead of (as a substitute for) fresh fruit; based on this reasoning, it would make sense for restaurants to get ready for the shift in demand toward eggs and away from fresh fruits—by adjusting their supplies accordingly. If you find this line of reasoning a bit questionable— in other words, if you think it’s full of holes—you’re on the right track! Proceed to Step 3.

Step 3: The question essentially asks how you’d weaken the argument. So now’s the time to critique it—to shoot some big holes in it. Ask yourself what else is needed to justify the recommendation, based solely on the premises. Doesn’t the logical leap from premises to conclusion rely on certain assumptions about a significant number of breakfast-restaurant patrons? Here are three such assumptions (have any of these occurred to you?):

• Customers are actually aware of the report (otherwise, why anticipate increased demand for eggs?).



• Customers would prefer eggs over fresh fruit, even if they knew about the report (otherwise, why anticipate a shift in demand from fresh fruit to eggs?).



• Customers consider eggs a suitable substitute for fresh fruit (otherwise, why decrease the supply of fresh fruit?).

Any one of these assumptions would form a good basis for a “best” answer to the question. To draft that best answer, all you’d need to do is refute any one of those assumptions—in other words, point out that any of the following is true:

• Customers are not aware of the report.



• Customers would not prefer eggs over fresh fruit (even if they knew about the report).



• Customers do not consider eggs a suitable substitute for fresh frui

Step 4: Notice that the statement in choice (D) (Many customers of breakfast restaurants who order eggs also order fresh fruit) is not quite the same as saying that eggs are not a substitute for fresh fruit (the last of our home-grown answers from Step 3). Yet, the essence of the critique is essentially the same: It’s unfair to assume, without any supporting evidence, that a significant number of customers are going to switch from fruit to eggs. Notice that (D) uses the word “many,” leaving open the possibility that for some customers, these two choices might be mutually exclusive. So does that mean that there’s probably a better answer choice? No; it’s a pretty safe bet that (D) is the best choice. But go ahead and consider the other choices, anyway, just in case. Tentatively earmark (D) as your selection, then continue to Step 5.

Step 5: Consider each of the other four answer choices in turn:

Choice (A) also tends to weaken the argument. (If eating eggs is risky, this fact would tend to discourage, rather than encourage, people from eating them.) But if (A) is to significantly weaken the argument, we need to assume that a significant percentage of breakfast-restaurant customers are males over the age of fifty. Since (A) depends heavily on this additional assumption, it is not as effective as (D) in weakening the argument. Earmark it as a “runner-up.”

Choice (B) is difficult to assess without more information, isn’t it? The fact that fresh fruits are seasonal might have a bearing on whether owners should decrease their fruit supplies at a particular time. (For example, you could argue that, when fresh fruit is plentiful, lowering the supply might be safer than when it is not.) But what does that have to do with increasing egg supply? Absolutely nothing. As you can see, it’s a real stretch to defend (B) as directly relevant to the argument at all, let alone as a statement that would clearly weaken the argument. Eliminate it!

Choice (C) provides a reason why restaurant owners might want to decrease their supply of eggs. So (C) does tend to weaken the argument. But (C) helps refute only half of what the argument recommends. What about the recommendation to decrease fresh fruit supplies? Whether alternatives to eggs are gaining in popularity has no clear relationship on the demand for fresh fruit. So earmark (C) as another “runner-up.”

Choice (E) provides a reason why restaurant owners might want to decrease their supply of fresh fruit—which is part of what the argument recommends. So (E) actually tends to support, or strengthen, the argument—just the opposite of what you’re looking for in the best choice. Eliminate (E)!

Step 6: Reflect again on the three most viable choices—the ones that tend to weaken the argument. Notice that choices (A) and (C), the two runners-up, both pale in comparison to (D) in terms of how seriously they weaken the argument. You can confidently confirm your selection: (D).

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