LSAT Strengthen Questions Practice Questions with Answers

LSAT Strengthen Questions Practice Questions with Answers

Logic games and reading comprehension often grab the headlines, but approximately 50% of the Logical Reasoning section depends on your ability to evaluate arguments. LSAT Strengthen Questions require you to identify the piece of information that, if true, would most increase the probability that the author's conclusion is valid. These questions test your ability to support a bridge between a premise and a conclusion, often by addressing a hidden assumption or eliminating a potential counter-argument.

Concept Explanation

LSAT Strengthen Questions are a specific type of Logical Reasoning task where you must select the answer choice that provides the most support for the argument's conclusion. Unlike "Must Be True" questions, the information in the answer choice is not necessarily derived from the stimulus; rather, you must treat each answer choice as a new fact. The goal is to find the information that best plugs a gap in the logic or bolsters the relationship between the evidence and the claim. Effective strategies for this section, much like reading strategies for other standardized tests, involve identifying the "core" of the argument: the conclusion and its supporting premises. By isolating the conclusion, you can determine exactly what needs help. A strengthener typically works by confirming a necessary assumption, providing additional data that supports the premise, or ruling out an alternative explanation that would otherwise weaken the case.

To excel at these, you should consult a comprehensive LSAT Prep hub to understand how arguments are structured. Most arguments fail because they assume a connection that isn't explicitly stated. For example, if an argument says, "The sun is out, so we should go to the beach," the hidden assumption is that sunny weather is a good reason to visit the beach. A strengthener might state, "Beaches are most enjoyable when the sun is shining."

Solved Examples

1. Example 1: The Health Supplement
   Argument: A recent study showed that people who took Vitamin X reported 20% fewer colds than those who did not. Therefore, Vitamin X prevents the common cold.
   Step-by-Step Solution:
   1. Identify the conclusion: Vitamin X prevents the common cold.
   2. Identify the premise: People taking it had 20% fewer colds.
   3. Find the gap: Correlation does not equal causation. Perhaps people who take vitamins are generally more health-conscious.
   4. Strengthen: An answer choice stating that "A double-blind study confirmed Vitamin X inhibits viral replication" would support the causal link.
2. Example 2: The Corporate Profit
   Argument: Company Y increased its advertising budget by 50% last year. Since Company Y’s profits rose by 10% in the same period, the advertising campaign was successful.
   Step-by-Step Solution:
   1. Identify the conclusion: The advertising campaign caused the profit increase.
   2. Identify the premise: Ad budget went up, and profits went up.
   3. Find the gap: Other factors (like a competitor going out of business) could have caused the profit rise.
   4. Strengthen: An answer choice stating that "Market demand for Company Y's products remained stable except in areas where the ads were shown" strengthens the link.
3. Example 3: The Ancient Pottery
   Argument: Archaeologists found Greek pottery in a 5th-century site in Britain. This proves that the British tribes of that era traded directly with Greek merchants.
   Step-by-Step Solution:
   1. Identify the conclusion: Direct trade existed between Britain and Greece.
   2. Identify the premise: Greek pottery was found in Britain.
   3. Find the gap: The pottery could have arrived via intermediate traders (e.g., Romans or Gauls).
   4. Strengthen: An answer choice stating "No other contemporary cultures in Europe possessed Greek pottery during this period" makes direct trade more likely.

Practice Questions

1. The city of Oakhaven recently installed new streetlights in the downtown area. Since the installation, the number of reported nighttime thefts has decreased by 15%. Therefore, the new streetlights have made Oakhaven safer. Which of the following, if true, most strengthens the argument?

2. Recent data shows that students who use the AI Flashcard Generator for at least one hour a week score significantly higher on the LSAT than those who do not. Thus, using digital flashcards is more effective than using paper notes for LSAT preparation. Which of the following most strengthens the conclusion?

3. A paleontologist argues that a specific dinosaur species was warm-blooded because its fossils were found in a region that was historically near the Arctic Circle. Which of the following most strengthens the paleontologist's argument?

4. Many coffee shops have seen a decline in sales over the last quarter. Because the price of coffee beans rose by 30% during this time, the increase in bean prices is responsible for the decline in shop profits. Which of the following, if true, most strengthens the argument?

5. A study found that children who play chess perform better in mathematics than those who do not. The researchers concluded that learning chess improves mathematical ability. Which of the following, if true, most strengthens the researchers' conclusion?

6. The local government claims that the new high-speed rail will reduce traffic congestion on Highway 101. They base this on a survey where 60% of commuters said they would prefer the train to driving. Which of the following most strengthens the government's claim?

7. A tech company noticed that employees who work from home are 15% more productive than those in the office. The CEO concluded that the lack of office distractions is the primary cause of this increased productivity. Which of the following most strengthens the CEO's conclusion?

8. Evidence suggests that the volcanic eruption on Island X caused the extinction of the local flightless bird. Layers of ash were found in the same geological strata as the last known bird fossils. Which of the following most strengthens the argument?

Answers & Explanations

1. Answer: There was no increase in the number of police patrols in Oakhaven during the period following the streetlight installation.
   Explanation: This strengthens the argument by ruling out an alternative cause (increased policing) for the reduction in theft.
2. Answer: Students who used the digital flashcards had similar baseline scores to those who used paper notes before beginning their study.
   Explanation: This ensures the higher scores weren't just due to the students being "smarter" or better prepared to begin with, strengthening the claim that the tool itself was the cause. You might find similar logic useful when evaluating vocabulary-in-context questions.
3. Answer: Cold-blooded animals cannot survive in temperatures as low as those found near the Arctic Circle during the period in question.
   Explanation: This provides a necessary link between the location (cold) and the biological trait (warm-bloodedness).
4. Answer: The number of customers visiting the coffee shops remained the same, but the shops raised prices to cover the cost of beans.
   Explanation: This connects the bean price increase directly to a change in the shop's financial structure that would affect profits.
5. Answer: The study followed children who previously had identical math scores and found that only those who began playing chess showed improvement.
   Explanation: This establishes a temporal sequence and controls for initial ability, strengthening the causal claim.
6. Answer: The survey respondents were representative of the commuters who currently cause the most congestion on Highway 101.
   Explanation: This ensures that the "preference" expressed in the survey will actually translate into a reduction in traffic where it matters most.
7. Answer: Employees who were moved from the office to home reported that they were able to complete tasks faster due to fewer interruptions.
   Explanation: This provides direct evidence for the mechanism (lack of distractions) proposed by the CEO.
8. Answer: Analysis of the bird fossils showed that the birds died from inhaling volcanic ash rather than from unrelated causes.
   Explanation: This provides a direct causal link between the eruption (ash) and the death of the birds.

Frequently Asked Questions

What is the difference between a Strengthen and a Justify question?

A strengthener simply makes the conclusion more likely, whereas a Justify (or Sufficient Assumption) question requires an answer that makes the conclusion 100% logically certain. Strengthening is a matter of degree, while justifying is a matter of logical necessity.

Can an answer choice be correct if it introduces new information?

Yes, LSAT Strengthen Questions almost always introduce new information. Your task is to determine how this new information interacts with the existing argument, rather than looking for something already mentioned in the text.

Should I look for the "most" strengthening answer or just any strengthener?

The LSAT asks for the choice that "most strengthens" the argument. While multiple choices might provide a tiny bit of support, one will clearly provide more significant logical backing or address a more critical flaw.

How do I handle "Except" strengthen questions?

In a "Strengthen... Except" question, four of the answers will strengthen the argument, and one will either weaken it or do nothing at all. The correct answer is the one that does NOT provide support.

Does a strengthener have to prove the conclusion?

No, a strengthener does not need to be sufficient to prove the conclusion. It only needs to move the needle in the direction of the conclusion being true, even if by a small amount.