The answer for the first question is very irrelevant. The language has nothing to do with anything mentioned in the argument.

This answer alludes to hidden variables, in this case the type of fat, which is not mentioned in the original argument because that line of logic treats all fats as the same. The point, and relevance, of this answer is to weaken the argument by pointing out that there are differences between types of fat, which the original argument failed to do appropriately.

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Course: LSAT > Unit 1

Lesson 6: Logical Reasoning – Articles

Strengthen and weaken | Learn more

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How do we identify information that would strengthen or weaken an argument?

Strengthen and Weaken questions ask you to find info that would make the conclusion of an argument more or less likely to be true, based on the evidence that's provided. A strengthener or weakener won’t necessarily prove or disprove an argument beyond a shadow of a doubt—it’ll just increase or decrease the likelihood that the conclusion follows from its support.

How do we identify these questions?

Strengthen:

Which one of the following, if true, most strongly supports the argument above?

Which one of the following, if true, most strengthens the ecologist’s reasoning?

Weaken:

Which one of the following, if true, most undermines the argument?

Which one of the following represents the strongest counter to Ana’s argument?

Which one of the following, if true, casts the most doubt on the reasoning above?

Let’s work through an example together!

Example

In its coverage of a controversy regarding a proposal to build a new freeway, a television news program showed interviews with several people who would be affected by the proposed freeway. Of the interviews shown, those conducted with people against the new freeway outnumbered those conducted with people for it two to one. The television program is therefore biased against the proposed freeway.

Which one of the following, if true, most seriously weakens the argument?

(A) Most of the people who watched the program were aware of the freeway controversy beforehand.

(B) Most viewers of television news programs do not expect those programs to be completely free of bias.

(C) In the interviews, the people against the new freeway expressed their opinions with more emotion than the people for the freeway did.

(D) Before the program aired, over twice as many people were against building the freeway than were in favor of it.

(E) The business interests of the television station that produced the program would be harmed by the construction of a new freeway.

How might we approach this question?

✓ Identify the argument’s conclusion and support.

It’s usually helpful to separate the arguer’s conclusion (which in this case is essentially an opinion) from the arguer’s evidence (which is information that we accept as true). That way, you can detect any important gaps that need to be addressed.

Conclusion: The television program is biased against the proposed freeway [because]

Support:

In its coverage of a controversy regarding a proposal to build a new freeway, a television news program showed interviews with several people who would be affected by the proposed freeway, [and]
Of the interviews shown, those conducted with people against the new freeway outnumbered those conducted with people for it two to one.

✓ Identify gaps in the argument.

How does the evidence connect to the conclusion? In our example question, the reason the arguer thinks that the television program is biased against the proposed freeway is that the program’s interviews showed twice as many interviews with people against the proposal as people supporting the proposal.

So, we could identify the gap as being between:

The higher number of broadcast interviews against the proposal, and
The television program’s bias against the proposal.

In other words, the arguer believes that the first thing (# of broadcast interviews for and against) proves the second thing (bias against proposal).

✓ Diagram if necessary.

Sometimes it’s helpful to draw a quick sketch of the action. If there is conditional logic (“if X then Y”), causal relationships that can be linked together, or any numbers and figures, seeing the info written down can help you organize your thoughts.

This example may not require a diagram, but it might help you to jot down a shorthand of the argument’s gap:

✓ Identify any common patterns.

In our example, there isn’t a classic pattern that’s immediately visible, but it’ll save you time on Test Day if you keep an eye out for any of the following:

Weaken a causal relationship (X caused Y): Show that there could be an alternate cause (Z caused Y).
Weaken a conclusion that’s based on a sample: Show that the sample isn’t big enough or relevant enough.
Strengthen a causal relationship (X caused Y): Show that a potential alternate cause isn’t actually the cause.
Strengthen an argument with different topics in the evidence and conclusion: Show that the topic in the evidence is related to the topic in the conclusion.

✓ Test each choice one at a time.

For certain types of Logical Reasoning questions, we recommend trying to make a specific answer prediction before heading to the choices. For Strengthen and Weaken questions, however, predictions aren’t recommended.

Why not? There’s usually a variety of possible strengtheners or weakeners for any given argument, and it’s generally not a productive use of your limited time on Test Day to brainstorm about all the various possibilities.

Additionally, it can be all too easy to forget whether you’re looking for a strengthener or a weakener, so it’s helpful to simply remind yourself of the task before you start to evaluate the choices.

In this argument, for example:

”I’m looking for a choice that shows that the higher number of broadcast interviews against the proposal doesn’t indicate that the television program is biased against the proposal

”I’m looking for information that helps show that the television program isn’t as biased as it initially looked, even though the ratio of interviewees was 2:1.”

Top tip: Add the choice to the argument. As you evaluate each choice, imagine that you’re adding the choice’s information to the argument. Which way does the argument move? There are only three things a choice could do:

strengthen the argument
weaken the argument
have no effect on the argument

Top tip: Don't overdo it! "Strengthen" doesn’t mean prove, and "weaken" doesn’t mean disprove. You don’t need to destroy an argument in order to weaken it; it's good enough to just make the conclusion less likely to follow from its evidence.

Go ahead and evaluate each choice, then click on the corresponding explanations below to check your reasoning.

(B) Most viewers of television news programs do not expect those programs to be completely free of bias.

Any additional information about viewers’ expectations doesn’t affect the argument, which claims that the program is biased. Even if the expectation is that the television news programs will be biased in some way, that doesn’t affect the argument that this television news program is biased against the freeway project. To weaken this argument, we need information that would show that maybe the news program isn’t biased against the project, and viewers’ expectations isn’t relevant to that.

(C) In the interviews, the people against the new freeway expressed their opinions with more emotion than the people for the freeway did.

This information doesn’t affect the argument or the strength of its reasoning. If anything, it even has the potential to strengthen the argument claiming bias, if it were known that the news program had intentionally chosen emotional interviews from people against the new freeway. But by itself, information about how emotional the interviewees were doesn’t move the argument one way or the other.

(D) Before the program aired, over twice as many people were against building the freeway than were in favor of it.

This information weakens the argument! If more than twice as many people were against the freeway project than were in favor of it, then it’s more likely that the news program was showing a representative sample of the population in its ratio of for/against interviews, and it’s less likely that the news program was actually biased.

Summary

✓ Identify the argument’s conclusion and support.
✓ Identify gaps in the argument.
✓ Diagram if you find it helpful!
✓ Identify any common patterns.
✓ Test each choice.

Your turn!

practice question 1

In a recent study of more than 400 North American men and women whose previous heart attack put them at risk for a second heart attack, about half were told to switch to a "Mediterranean-type diet"—one rich in fish, vegetables, olive oil, and grains—while the other half were advised to eat a more traditional "Western" diet but to limit their fat intake. Those following the Mediterranean diet were significantly less likely than those in the other group to have a second heart attack. But the Mediterranean diet includes a fair amount of fat from fish and olive oil, so the research suggests that a diet may not have to be extremely low in fat in order to protect the heart.

Which one of the following, if true, most strengthens the argument?

(Choice A)
Research has shown that eliminating almost all fat from one's diet can be effective in decreasing the likelihood of a second heart attack.
(Choice B)
Studies suggest that the kinds of oils in the fat included in the Mediterranean diet may protect the heart against potentially fatal disruptions of heart rhythms and other causes of heart attacks.
(Choice C)
The patients who consumed the Mediterranean diet enjoyed the food and continued to follow the diet after the experiment was concluded.
(Choice D)
Many people who have had heart attacks are advised by their cardiologists to begin an exercise regimen in addition to changing their diet.
(Choice E)
Some cardiologists believe that the protection afforded by the Mediterranean diet might be enhanced by drugs that lower blood-cholesterol levels.

It’s usually helpful to separate the argument into its conclusion and support:

Conclusion: A diet may not have to be extremely low in fat in order to protect the heart

because

Support: People who switched to a Mediterranean diet, which includes a fair amount of fat from fish and olive oil, were significantly less likely to have a second heart attack than those eating the Western diet.

Since we don’t usually make a specific prediction for Strengthen and Weaken questions, can you sum up your task before heading into the choices?

Based on our argument analysis, we could make a prediction that sounds something like this:

“I’m looking for a choice that gives me information that makes it more likely that a diet doesn’t have to be low-fat to protect the heart, given that the people who switched to a fairly fatty diet were less likely to have another heart attack than the people on the Western diet.”

I want to help the arguer. And the arguer thinks that a diet doesn’t have to be low-fat to protect the heart; it could be fatty, like the Mediterranean diet that people switched to but still saw a heart benefit.

Which choice accomplishes your task?

Practice question 2

In order to determine automobile insurance premiums for a driver, insurance companies calculate various risk factors; as the risk factors increase, so does the premium. Certain factors, such as the driver's age and past accident history, play an important role in these calculations. Yet these premiums should also increase with the frequency with which a person drives. After all, a person's chance of being involved in a mishap increases in proportion to the number of times that person drives.

Which one of the following, if true, most undermines the argument?

(Choice A)
People who drive infrequently are more likely to be involved in accidents that occur on small roads than in highway accidents.
(Choice B)
People who drive infrequently are less likely to follow rules for safe driving than are people who drive frequently.
(Choice C)
People who drive infrequently are less likely to violate local speed limits than are people who drive frequently.
(Choice D)
People who drive frequently are more likely to make long-distance trips in the course of a year than are people who drive infrequently.
(Choice E)
People who drive frequently are more likely to become distracted while driving than are people who drive infrequently.

The argument can be analyzed in this way:

Conclusion: [Automobile insurance] premiums should increase with the frequency with which a person drives [because]

Support:

Certain factors, such as the driver’s age and past accident history, play an important role in [calculating premiums], [and]
A person’s chance of being involved in a mishap increases in proportion to the number of times that person drives.

Can you state your task in a general way, so that you know what the answer should accomplish?

Here are a couple of ways you could sum up your task:

“I’m looking for information that makes me think that maybe people who drive more frequently should actually have lower premiums than people who drive less frequently, or maybe information that shows that frequency doesn’t matter.”

“The arguer thinks that more driving means more risk. I want to find the choice that hurts that relationship.”

Which choice accomplishes our task?

Practice question 3

High school students who feel that they are not succeeding in school often drop out before graduating and go to work. Last year, however, the city's high school dropout rate was significantly lower than the previous year's rate. This is encouraging evidence that the program instituted two years ago to improve the morale of high school students has begun to take effect to reduce dropouts.

Which one of the following, if true about the last year, most seriously weakens the argument?

(Choice A)
There was a recession that caused a high level of unemployment in the city.
(Choice B)
The morale of students who dropped out of high school had been low even before they reached high school.
(Choice C)
As in the preceding year, more high school students remained in school than dropped out.
(Choice D)
High schools in the city established placement offices to assist their graduates in obtaining employment.
(Choice E)
The antidropout program was primarily aimed at improving students' morale in those high schools with the highest dropout rates.

We can separate our conclusion and evidence in this way:

Conclusion: The program instituted two years ago to improve the morale of high school students has begun to take effective to reduce dropouts [because]

Support:

High school students who feel that they are not succeeding in school often drop out before graduating and go to work, [but]
Last year, the city's high school dropout rate was significantly lower than the previous year's rate.

The arguer is essentially seeing a correlation between a new program and a lower dropout rate, and concludes that the program is working. What is our task, in your own words?

Because we need to weaken the argument, we won’t name anything specific (since there are so many possibilities), but let’s prepare ourselves with a prediction—something like:

“I’m looking for a choice that somehow separates the new program and the lower dropout rate, and might indicate that something else could have caused the lower dropout rate to happen, or that the program and the dropout rate aren’t actually connected.”

“The answer will have some kind of information that makes it less likely that the new program caused the lower dropout rate.”

Which choice does what we’re looking for?

practice question 4

Consumer advocate: The introduction of a new drug into the marketplace should be contingent upon our having a good understanding of its social impact. However, the social impact of the newly marketed antihistamine is far from clear. It is obvious, then, that there should be a general reduction in the pace of bringing to the marketplace new drugs that are now being tested.

Which one of the following, if true, most strengthens the argument?

(Choice A)
The social impact of the new antihistamine is much better understood than that of most new drugs being tested.
(Choice B)
The social impact of some of the new drugs being tested is poorly understood.
(Choice C)
The economic success of some drugs is inversely proportional to how well we understand their social impact.
(Choice D)
The new antihistamine is chemically similar to some of the new drugs being tested.
(Choice E)
The new antihistamine should be on the market only if most new drugs being tested should be on the market also.

We can separate our conclusion and evidence like this:

Conclusion: There should be a general reduction in the pace of bringing to the marketplace new drugs that are now being tested [because]

Support:

The introduction of a new drug into the marketplace should be contingent upon our having a good understanding of its social impact, [but]
The social impact of the newly marketed antihistamine is far from clear.

Can you identify a gap? In other words, how is what’s being addressed in the evidence separated from what’s being addressed in the conclusion in an important way?

The arguer shows that the social impact of newly marketed antihistamine is far from clear, but then draws a conclusion about what should be done about new drugs that are now being tested. These aren’t necessarily related, since the newly marketed antihistamine could be an outlier. In other words, how do we know that the newly marketed antihistamine is representative of other drugs being tested? What if the antihistamine is the only one that we don’t understand, but the social impact of all the other drugs are well-understood? That would weaken this argument.

Since we’re asked to strengthen this argument, what’s a good description of what we expect the answer to do?

Practice Question 5

Nutritionists believe that a person's daily requirement for vitamins can readily be met by eating five servings of fruits and vegetables daily. However, most people eat far less than this. Thus, most people need to take vitamin pills.

Which one of the following statements, if true, most seriously weakens the argument?

(Choice A)
Even five servings of fruits and vegetables a day is insufficient unless the intake is varied to ensure that different vitamins are consumed.
(Choice B)
Certain commonly available fruits and vegetables contain considerably more nutrients than others.
(Choice C)
Nutritionists sometimes disagree on how much of a fruit or vegetable constitutes a complete serving.
(Choice D)
Many commonly consumed foods that are neither fruits nor vegetables are fortified by manufacturers with the vitamins found in fruits and vegetables.
(Choice E)
Fruits and vegetables are also important sources of fiber, in forms not found in vitamin pills.

Be careful here. We want the speaker's—not the nutritionists'—conclusion and evidence:

Conclusion: Most people need to take vitamin pills [because]

Support:

Nutritionists believe that a person's daily requirement for vitamins can readily be met by eating five servings of fruits and vegetables daily, but
Most people eat far less than this.

Do you see any gaps in this argument? What about overlooked possibilities?

Nutritionists think that eating five servings of fruits and veggies is sufficient to meet a person’s daily vitamin requirement, but that doesn’t mean that eating five servings of fruits and veggies is necessary. What if people could get their vitamins through other kinds of food besides fruits and vegetables?

This argument presents an either/or scenario that we could weaken by showing that the situation isn't actually either/or. In other words, there could be an altogether different path to meeting one's daily requirement for vitamins than what's presented.

Do any of the choices indicate this kind of overlooked possibility?

Practice Question 6

Toxicologist: A survey of oil-refinery workers who work with MBTE, an ingredient currently used in some smog-reducing gasolines, found an alarming incidence of complaints about headaches, fatigue, and shortness of breath. Since gasoline containing MBTE will soon be widely used, we can expect an increased incidence of headaches, fatigue, and shortness of breath.

Each of the following, if true, strengthens the toxicologist's argument EXCEPT:

(Choice A)
Most oil-refinery workers who do not work with MBTE do not have serious health problems involving headaches, fatigue, and shortness of breath.
(Choice B)
Headaches, fatigue, and shortness of breath are among the symptoms of several medical conditions that are potentially serious threats to public health.
(Choice C)
Since the time when gasoline containing MBTE was first introduced in a few metropolitan areas, those areas reported an increase in the number of complaints about headaches, fatigue, and shortness of breath.
(Choice D)
Regions in which only gasoline containing MBTE is used have a much greater incidence of headaches, fatigue, and shortness of breath than do similar regions in which only MBTE-free gasoline is used.
(Choice E)
The oil-refinery workers surveyed were carefully selected to be representative of the broader population in their medical histories prior to exposure to MBTE, as well as in other relevant respects.

Conclusion: We can expect an increased incidence of headaches, fatigue, and shortness of breath [from the wide use of gasoline containing MBTE that's coming]

because

Support: A survey of oil-refinery workers who work with MBTE, an ingredient currently used in some smog-reducing gasolines, found an alarming incidence of complaints about headaches, fatigue, and shortness of breath.

Is there a gap in this argument?

The arguer moves from evidence about oil-refinery workers who suffer ill effects from MBTE to a conclusion about more widespread ill effects from a wider user of MBTE. Since we know there will be four strengtheners in the choices, that means there are several gaps in the argument.

One classic pattern we see here is of causation and correlation: it's not demonstrated that MBTE is actually causing the ill effects, since the evidence is just a correlation. So a strengthener might rule out potential threats to that causal relationship.

Which choice doesn't help the toxicologist's argument, either because it weakens the argument, or because it has no effect on the argument?

Some final thoughts on strengthen and weaken questions

Pay attention to degree. Strengtheners and weakeners will vary in degree; some will strengthen or weaken dramatically, while others will strengthen or weaken more subtly.
Add the choice to the argument. It helps many students to imagine that they’re adding a choice to the passage itself, so that they can ask, “Which way did the argument move after I added that information? Did it even move at all?”
Sum up the task. While we can make very specific predictions for question types such as Flaw, Assumption, and Technique (to name a few), it’s better to generate only a general prediction for Strengthen and Weaken questions. That’s because there are often many ways that a given argument could be strengthened or weakened. You can make a general prediction by saying something like, “I’m looking for information that makes it more/less likely that [conclusion], based on the given evidence that [evidence].”
“No effect” choices can be right on EXCEPT questions. For Strengthen EXCEPT questions, the answer will either weaken or have no effect. For Weaken EXCEPT questions, the answer will either strengthen or have no effect. Students often overlook the possibility that a “no effect” choice also qualifies as the answer, so keep that in mind when faced with a Strengthen/Weaken EXCEPT question.

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cstochl5
Posted a year ago. Direct link to cstochl5's post “For Practice Question 3, ...”
For Practice Question 3, wouldn't the establishment of placement offices to assist their graduates in obtaining employment provide an incentive for current high school students to stick around until graduation, and therefore decrease the dropout rate? I understand that a recession may have a bigger influence and thus be the answer, but I still find that there can be a case made here.
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(5 votes)
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LyricLinXiaoli
Posted 4 months ago. Direct link to LyricLinXiaoli's post “Practice question 6 has a...”
Practice question 6 has a wording mistake. The explanations suggest that it's a weakener practice, but the question itself asks “Each of the following, if true, STRENGTHENS the toxicologist's argument...”
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(2 votes)
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leziahg
Posted 2 years ago. Direct link to leziahg's post “The answer for the first ...”
The answer for the first question is very irrelevant. The language has nothing to do with anything mentioned in the argument.
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(0 votes)
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- Kaileigh Row
  Posted 2 years ago. Direct link to Kaileigh Row's post “This answer alludes to hi...”
  This answer alludes to hidden variables, in this case the type of fat, which is not mentioned in the original argument because that line of logic treats all fats as the same. The point, and relevance, of this answer is to weaken the argument by pointing out that there are differences between types of fat, which the original argument failed to do appropriately.
  Button navigates to signup page
  (6 votes)