Throughout this chapter, you have learned about the standard Critical Reasoning question types on the GMAT. Recognizing these formulaic question types enables you to read strategically—that is, to read for the details that make the difference between right and wrong answers. But the arguments in CR stimuli follow patterns as well. Recognizing common argument structures will allow you to analyze stimuli and predict correct answers more efficiently.
These advanced techniques are no substitute for knowing how to identify the conclusion, evidence, and assumptions in arguments—the ability to break down arguments into their component parts remains essential—but the three special cases we are about to discuss can help you zero in on the author’s central assumption with speed and accuracy. When you understand the kind of argument an author is making, you can anticipate what kind of assumptions he or she is likely to make.
The three special cases are Causality; Representativeness; and Plans, Proposals, and Predictions. Causality and Representativeness are classic argument structures, and Plans, Proposals, and Predictions are classic argument conclusions that function in predictable ways.
Let’s begin by discussing how to identify a causal argument and use that knowledge to your advantage on Critical Reasoning questions.
A causal argument is an assertion that a certain cause produced a certain effect. In other words, X caused Y, X made Y happen, or Y is the result of X. The author’s assertion of causality may be explicit (e.g., “The drought led to large-scale crop failures,” or “The new city plan is responsible for these underdeveloped downtown blocks”) or implicit (e.g., “Since the introduction of the new radiator design, brand X cars have seen an 8 percent increase in incidents of overheating. Customer dissatisfaction will remain high until we announce a redesign”). Examine the following example of a conclusion that contains a claim of causality:
Married people have been shown in several important studies to have higher levels of happiness than single people. Therefore, marriage causes happiness.
This argument draws its validity from a stated cause-effect relationship (namely, that marriage causes happiness). A conclusion that X caused Y relies on certain assumptions: (1) that nothing else—A, B, C, etc.—could have caused Y; (2) that Y was not the cause of X; and (3) that the apparent relationship between X and Y wasn’t just a coincidence. An author who makes any of these assumptions may be confusing correlation and causation.
Causal conclusions often appear in Weaken stimuli. There are three ways to weaken causal arguments based on the assumptions listed above. Let’s try them out with the following cause-effect statement:
“Marriage causes happiness.”
X = cause (marriage); Y = effect (happiness)
Patterns for weakening a causal argument:
Alternative explanation: It wasn’t X that caused Y; it was actually Z that caused Y.
“Marriage doesn’t cause happiness; in fact, financial security (which correlates strongly with marriage) was the real cause of the happiness reported in the surveys.”
Causality reversed: It wasn’t X that caused Y; it was actually Y that caused X.
“Marriage doesn’t cause happiness; in fact, people who are already happy are significantly more likely to marry.”
Coincidence: It wasn’t X that caused Y; any correlation between X and Y is a coincidence, since they have no direct relationship.
“Marriage doesn’t cause happiness; other studies that looked at the same group of people over time found that people reported similar levels of happiness before and after getting married. Any seeming correlation between marriage and happiness is coincidental or based on other factors.”
In Weaken questions involving causality, the first of these three weakeners (alternative explanation) is the most common. It can be difficult to predict the specific alternative cause that will appear in the correct answer. You do know, however, that the right answer will provide a plausible explanation other than the one the author assumes to be true. The introduction of a plausible alternative cause undermines the author’s conclusion.
Now let’s use the Kaplan Method for Critical Reasoning to solve a question involving causality:
For the past year, a network television talk-show host has been making fun of the name of a particular brand of chainsaw, the Tree Toppler. The ridicule is obviously taking its toll: in the past 12 months, sales of the Tree Toppler have declined by 15 percent, while the sales of other chainsaws have increased.
Which of the following, if true, casts the most serious doubt on the conclusion drawn above?
Because this stem asks you to “cast doubt” on the conclusion, this is a Weaken question.
For the last year, a talk-show host has been ridiculing Tree Toppler chainsaws. Over that time, Tree Toppler sales have fallen while other chainsaws’ sales have risen. The author concludes that the talk-show host’s jokes must have caused the declining Tree Toppler sales.
To weaken an argument in which X is claimed to have caused Y, consider whether Y might actually have caused X (i.e., reversal) or whether something else might have caused Y (i.e., alternative cause). In this case, it seems unlikely that the decline in sales caused the on-air ridicule; the host is making fun of the chainsaw’s name, not its declining sales. Therefore, the correct answer to this Weaken question will probably offer some alternative explanation for the decline in Tree Toppler sales.
(E) provides that alternative explanation. If a prominent magazine rates a chainsaw as unsafe, that could certainly deter people from purchasing it, and a subsequent decline in sales would be reasonable to expect. (E) matches the prediction and is the correct answer.
If you hadn’t immediately recognized (E) as a match for your prediction, you could still find the right answer by eliminating answer choices that miss the mark. Even if the talk-show host actually owns a Tree Toppler, as (A) says, the decline in sales could still be caused by the host’s on-air ridicule; (A) is irrelevant. (B) is a 180 because it actually strengthens the argument by eliminating a potential alternative explanation for the decline in sales. (C) might be tempting, but the argument actually mentions that sales of other chainsaws have increased, so an increase in the purchase price of all chainsaws is not a reasonable alternative explanation. (D) also strengthens the argument by eliminating another alternative explanation for the decline in sales (that fewer stores are carrying the Tree Toppler).
Note that relevant alternative explanations for a causal relationship may, at first glance, appear to have no bearing on the argument. But this is precisely because the author failed to recognize that there was an alternative possibility. Before you move to the answer choices, come up with two or three specific alternative explanations. Focus on the effect each answer choice has on the alleged causal relationship. By weakening the causal relationship, the correct answer choice will undermine the logic of the argument.
When GMAT arguments include evidence in the form of surveys, studies, polls, anecdotes, or experiments, a key issue is often the representativeness of the group used as evidence. You may be familiar with the idea of representativeness from a statistics or research methods class. This concept is no different on the GMAT. In order to be representative, a sample must be large enough, the survey length must have covered an adequate amount of time, and the population surveyed cannot be biased in some flawed way.
In GMAT arguments, the author always believes that her evidence leads to her conclusion. Therefore, the author who uses statistical evidence always assumes the data are relevant to the conclusion. But in order for this to be the case, the sample used in the evidence must be representative of the group to which the conclusion is applied. Oftentimes on GMAT questions, the sample will fail to provide sufficient evidence to fully support the conclusion.
Now let’s use the Kaplan Method for Critical Reasoning to solve a question involving representativeness:
Candidate A was widely believed to be the favorite in her state’s gubernatorial race. Candidate B, the incumbent governor, had figured prominently in a corruption scandal during the previous year. Although he was ultimately never charged with a crime, Candidate B received very negative coverage in local and national media. A poll of registered voters in the state showed that a majority supported Candidate A and would vote for her. In fact, election day “exit polls” of those who voted showed that most had voted for Candidate A, so she was expected to win. However, once the votes were counted, Candidate B was shown to have won a narrow victory. Clearly, respondents to the polls were not being honest when they claimed to have supported Candidate A.
The argument above depends on which of the following assumptions?
This question directs you to find an assumption on which the argument depends, so this is definitely an Assumption question.
The argument concludes that respondents to recent election exit polls and preelection polls were not being honest when they claimed to have supported Candidate A for governor. The evidence for this is that despite a strong showing in these polls, Candidate A still lost the election.
This conclusion is based in part on the results of two polls, so those polls need to have been conducted with representative samples in order for the conclusion to be valid. After all, what if the polls had both been conducted outside campaign rallies for Candidate A or in Candidate A’s hometown? The sample group for the polls needs to be an adequate cross section of the voting population, and since this argument stakes its conclusion on the polls, the author of the argument must be assuming that the sample is indeed representative.
This question shows you that Kaplan’s strategy for representativeness is not restricted to Strengthen and Weaken questions. On Test Day, if you’re asked an Assumption question and you notice that the stimulus focuses on a study, survey, poll, or experiment, know that a choice that essentially says, “The sample was representative” is likely to be correct.
(E) matches this prediction perfectly and is the correct answer. If you used the Denial Test to negate (E), by stating that the poll’s sample group was not representative, then the author’s conclusion that voters must have lied can no longer be valid. If the people who participated in the polls were not representative of the larger voting population, then there would be no particular reason to expect the poll and voting results to be similar. (E) is therefore a necessary assumption of the argument.
(A) is not necessary to the argument because the author doesn’t base her conclusion on a prediction drawn from the press coverage. Rather, the author bases her conclusion on a prediction drawn from the polling data. (B), if true, would strengthen the argument, but this isn’t a Strengthen question; the right answer to an Assumption question must be something upon which the argument relies. While the argument asserts that people polled lied about whom they voted for, it does not depend on any particular reason why they did so. (C) is far too extreme; the argument’s point that the polls’ respondents lied is not undone if one or two people simply changed their minds. As for (D), the author doesn’t necessarily assume anything about how Candidate B was able to eke out a victory.
Once you start identifying plans, proposals, and predictions in Critical Reasoning stimuli, you’ll realize that many arguments contain conclusions in these forms. All three have a future orientation and indicate the author’s opinion.
Plans and proposals are found in conclusions that begin, “Thus, we should . . .” or “It’s in the company’s best interest to . . .” When a conclusion takes the form of a plan or proposal, the author is likely assuming that the plan or proposal is helpful and practical under the current circumstances. GMAT questions often test whether we realize that it may not be helpful or currently practical.
Critical Reasoning stimuli involving plans or proposals almost invariably offer only one reason for the plan or proposal. In other words, because of X, we should do Y.
So, what must the author be assuming about that evidence? That it’s the only, or at least the most important, factor to consider. Thus, any answer that introduces an alternative and competing consideration weakens the argument. Any answer that rules out a possible alternative consideration strengthens it.
Think about how you might weaken the following proposal:
Sam often oversleeps because he reaches over and turns off the alarm before he’s fully awake. To fix this problem, Sam proposes buying a second alarm clock.
Sam’s proposal is inherently flawed because it fails to consider some important factors: Sam might put the second clock right next to the first one and just shut it off, too. Alternatively, Sam might have to plug the second clock in too far from his bed. Then, he couldn’t hear it, so it wouldn’t be of any help. Either way, there’s an intervening consideration that suggests the plan will fail or will be self-defeating.
This happens in the business world all the time. For example, a sales manager might say, “Let’s do X and increase sales. That will make us profitable.” The operations manager might then respond, “Doing X would cost too much; this plan will lose money.” The problem is not that the sales manager is unreasonable in claiming that proposal X would increase sales—it might, in fact, do so. However, the operations manager raises another concern, one that the sales manager overlooked, that could undermine proposal X’s chance of success.
Predictions are no different in CR questions than they are in real life; they use the future tense: “So-and-so will win the Oscar,” “The economy will show modest growth,” or “We will not be able to meet the production deadline.” GMAT authors base their predictions on past and current trends or situations. In order to weaken such an argument, you want to find an answer choice that says that the trend will change. To strengthen it, look for an answer choice that says, “Future events will unfold as expected.”
Now let’s use the Kaplan Method for Critical Reasoning to solve a question involving a plan, proposal, or prediction:
Several people have died while canoeing during high water on a nearby river in recent years. The local police have proposed a ban on canoeing when the river reaches flood stage. Opponents of the ban argue that the government should ban an activity only if it harms people other than those who willingly participate in the activity, and they therefore conclude that the proposed ban on high-water canoeing is unwarranted.
Which of the following, if true, most seriously weakens the opponents’ conclusion?
The stem contains the obvious keyword “weakens,” but it also asks you to weaken the opponents’ conclusion in particular. Keep this information in mind—there may be more than one argument in the stimulus.
The government shouldn’t ban an activity that poses no risk to people who don’t voluntarily participate. Therefore, the opponents argue, the government should not ban high-water canoeing.
To weaken the argument, you need an answer choice that explains why the opponents’ proposal should, on its own terms, be rejected. Here, the opponents assume that high-water canoeing does not harm anyone who does not willingly participate in the canoeing. To weaken the conclusion, look for an answer choice suggesting that canoeing during flood stage does in fact threaten people other than those who have chosen to canoe.
(C) offers such a suggestion by stating that police officers, none of whom consented to expose themselves to the dangers of canoeing in high water, were in fact harmed as a result of such canoeing. (C) is the correct answer.
(A) has no bearing on the argument; it isn’t clear how sailing on a lake during high wind is relevant to canoeing on a river during high water. This statement tells us nothing about whether high-water canoeing poses risks to non-canoers. And just because, as (B) says, other governments have also enacted the bans, that doesn’t mean that the bans are necessarily reasonable. The opponents might still have a valid argument. Therefore, (B) is also irrelevant. (D) offers an irrelevant comparison: that more canoeists drown while the river is at normal levels may simply be due to the fact that there are more canoeists at that time to begin with. That has no bearing on whether canoeing should be banned at high water levels. And (E) might be tempting, but it doesn’t show that the opponents’ proposal to abolish the ban won’t work on its own terms. (E) doesn’t give an example of non-canoeists harmed by the canoeing.