LSAT Weaken Questions With Answers Practice Questions with Answers

LSAT Weaken Questions With Answers Practice Questions with Answers

Logical reasoning sections on the Law School Admission Test (LSAT) frequently require you to identify the specific vulnerability in an argument's structure. These tasks, known as LSAT weaken questions with answers, challenge your ability to spot assumptions and find new information that makes a conclusion less likely to be true. According to the Law School Admission Council (LSAC), these questions test the analytical skills essential for success in legal education.

Concept Explanation

LSAT weaken questions function by asking you to select the piece of information that most undermines the relationship between an argument's premises and its conclusion. To weaken an argument, you do not necessarily need to prove the conclusion is false; rather, you must introduce a fact that makes the conclusion less supported by the provided evidence. This usually involves attacking a hidden assumption or suggesting an alternative explanation for the observed facts. In your LSAT Prep journey, you will find that these questions are not about finding a "perfect" rebuttal, but the "best" available choice that casts doubt on the reasoning.

Effective strategies for tackling these items include:

• Isolate the Conclusion: Identify exactly what the author is trying to prove.
• Identify the Evidence: Look at the premises offered to support that conclusion.
• Find the Gap: Determine the assumption the author is making to bridge the premises and the conclusion.
• Introduce New Information: Unlike Inference questions, Weaken questions allow (and require) you to bring in outside information from the answer choices.

Solved Examples

Example 1: The Health Supplement Argument

Argument: A recent study showed that people who take Vitamin X daily have 20% fewer colds than those who do not. Therefore, Vitamin X prevents the common cold.

1. Analyze the structure: The premise is a correlation (Vitamin X and fewer colds). The conclusion is a causal claim (Vitamin X prevents colds).
2. Find the assumption: The author assumes that Vitamin X is the cause, rather than some other factor.
3. Weaken the argument: An answer choice stating that "People who take Vitamin X are also more likely to exercise and eat a balanced diet" weakens the argument by suggesting an alternative cause for the health benefits.

Example 2: The Corporate Productivity Argument

Argument: Company Y implemented a new four-day work week, and profits rose by 10% in the first quarter. Clearly, the four-day work week is the reason for the profit increase.

1. Analyze the structure: Premise (New schedule, followed by profit). Conclusion (Schedule caused profit).
2. Find the assumption: The author assumes no other external factors influenced profits during that quarter.
3. Weaken the argument: A choice noting that "Company Y's main competitor went out of business at the start of the first quarter" weakens the claim by providing a different explanation for the profit surge.

Example 3: The Rare Bird Argument

Argument: Sightings of the rare Golden Finch have doubled in the North Woods this year. This proves that the population of Golden Finches is increasing.

1. Analyze the structure: Premise (More sightings). Conclusion (More birds).
2. Find the assumption: The author assumes the number of sightings is a direct proxy for the actual population size.
3. Weaken the argument: If we learn that "A new bird-watching trail opened in the North Woods this year, attracting three times as many observers," the link between sightings and bird population is weakened.

Practice Questions

1. A local government official claims that installing traffic cameras at intersections has reduced accidents by 15%. The official concludes that the cameras are an effective tool for improving road safety. Which of the following, if true, most weakens the official's conclusion?

2. Most successful entrepreneurs have a background in competitive sports. Therefore, the discipline learned in sports is the primary driver of success in the business world. Which of the following most undermines this reasoning?

3. A study found that cities with more parks have lower rates of respiratory illness. The researchers concluded that the trees in the parks are filtering pollutants from the air, leading to better health outcomes. Which of the following, if true, casts the most doubt on the researchers' conclusion?

4. Since the introduction of a new standardized test, student scores in Mathematics have increased by 5 points. The school board claims the new curriculum is working. Which of the following weakens this claim?

5. A tech company noticed that employees who drink coffee are 30% more productive than those who do not. The CEO decides to provide free coffee to everyone to boost overall company productivity. Which of the following most strongly suggests the CEO's plan will fail?

6. Farmers who used Pesticide Z saw a 50% reduction in crop damage compared to last year. The manufacturer claims Pesticide Z is the most effective pest control on the market. Which of the following weakens this claim?

7. A recent poll shows that 70% of residents support the construction of a new stadium. Therefore, the city council should approve the project because it is in the public interest. Which of the following most weakens the argument?

8. Studies show that children who play musical instruments perform better on geometry tests. The school principal concludes that learning music enhances spatial reasoning skills. Which of the following most weakens this conclusion?

Answers & Explanations

1. Answer: The city also lowered the speed limits on all roads with traffic cameras during the same period. Explanation: This introduces a confounding variable, suggesting the speed limit change, not the cameras, might be responsible for the accident reduction.
2. Answer: The financial resources required to participate in competitive sports are the same resources needed to start a business. Explanation: This suggests a third factor (wealth) causes both sports participation and business success, weakening the direct link between sports discipline and success.
3. Answer: Cities with more parks are generally wealthier and have less industrial manufacturing. Explanation: This points to a lack of industrial pollution as the cause of lower illness rates, rather than the filtering effect of trees.
4. Answer: The new standardized test is significantly easier than the previous version. Explanation: If the test is easier, the score increase is likely due to the test design rather than an improvement in student ability or the curriculum.
5. Answer: Employees who are naturally high-performers are the ones most likely to drink coffee to maintain their pace. Explanation: This suggests that high productivity causes coffee consumption (reverse causation), rather than coffee causing productivity.
6. Answer: An unusually cold winter in the region killed off the majority of crop-destroying pests. Explanation: This provides an external environmental reason for the reduction in crop damage, undermining the claim that the pesticide was the cause.
7. Answer: The poll only surveyed residents living in the immediate vicinity of the proposed stadium site who would benefit from increased property values. Explanation: This indicates a biased sample, meaning the 70% support figure may not represent the city's general population interest.
8. Answer: Children with high natural spatial reasoning skills are more likely to be drawn to and persist in musical training. Explanation: This suggests that the trait (spatial reasoning) leads to the activity (music), rather than the activity developing the trait.

Frequently Asked Questions

Do I need to prove the conclusion is 100% false?

No, you only need to find the choice that makes the conclusion less likely to be true. A weakener just needs to cast doubt, not provide a complete refutation.

Can the answer choices contain new information?

Yes, unlike "Must Be True" questions, Weaken questions almost always introduce new facts. You should accept the information in the answer choices as true for the sake of evaluating its impact on the argument.

How do I handle arguments that use percentages?

Be wary of arguments that confuse percentages with absolute numbers. A 50% increase in a small number is still a small number, which can be a point of vulnerability to exploit when weakening. For more on quantitative reasoning, check out math-related logic strategies.

What is the difference between a Flaw question and a Weaken question?

A Flaw question asks you to describe an error in reasoning that is already present. A Weaken question asks you to pick a new fact that actively attacks the argument's support structure.

Should I look for the most extreme answer?

While "stronger" language can be helpful in Weaken questions, the most important thing is that the choice directly addresses the gap between the premise and the conclusion. Sometimes a subtle fact is more damaging than a broad generalization.