Examkin

Weaken

51 questions

All types51Multiple choice26True / False13Matching12
Question 1Question →

A recent study of municipal programs found that cities instituting "pay-as-you-throw" waste disposal systems—where residents are charged a fee based on the weight of their non-recyclable trash—saw a 40 percent increase in the total tonnage of materials collected in residential recycling bins during the first year. The study's authors conclude from this that the financial penalty successfully motivated residents to properly sort and recycle a much larger proportion of their eligible household waste.

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

Show answer & explanation

Answer: In the year following the system's implementation, recycling facilities in these cities reported a drastic increase in heavy, non-recyclable garbage being improperly disposed of in residential recycling bins.

Answer

The correct answer is the one stating that facilities reported a drastic increase in heavy, non-recyclable garbage being improperly disposed of in residential recycling bins.
The correct answer successfully weakens the argument by providing an alternative explanation for the 40 percent increase in tonnage. If residents are putting heavy, non-recyclable trash into their recycling bins to avoid paying the new weight-based fees for normal trash, then the increased weight in the recycling bins does not mean they are 'properly sorting and recycling' more eligible waste. This completely severs the logical link between the statistical premise and the behavioral conclusion.

Step-by-Step Solution

1
Identify the argument's premise and conclusion.
Premise: Tonnage of materials in recycling bins increased by 40% after implementing a fee for non-recyclable trash. Conclusion: The fee motivated residents to properly sort and recycle more eligible waste.
Isolating the gap between the evidence provided and the author's interpretation is the first step in any Weaken question.
2
Analyze the logical gap in the author's reasoning.
The author assumes that the increased weight in the recycling bins is composed strictly of properly sorted, eligible recyclable waste.
In Weaken questions based on statistics or data, the conclusion often misinterprets what the data actually represents or ignores alternative causes.
3
Evaluate the answer choices to find a statement that exploits this specific logical gap.
The option regarding heavy, non-recyclable garbage being improperly placed in recycling bins directly attacks the assumption by providing an alternative explanation for the increased tonnage.
If the increased weight is actually due to residents cheating the system to avoid fees, then they are not properly sorting their waste, which destroys the conclusion.

Key Concept

Identifying Alternative Explanations for Correlated Data
Estimated Time:1m 30s
Question 2Question →

City Councilor: Our new municipal tax on sugary beverages, implemented one year ago, has been a resounding success in improving public health. We know this because retail data shows that the total volume of sugary beverages sold within the city limits has decreased by 20% since the tax was introduced.

Which of the following, if true, most seriously weakens the city councilor's argument?

Show answer & explanation

Answer: Since the tax was implemented, sales of sugary beverages at stores immediately outside the city limits have surged by an amount roughly equal to the decrease seen within the city.

Answer

The statement regarding the surge in sales of sugary beverages at stores immediately outside the city limits most seriously weakens the argument.
The argument relies on the assumption that lower beverage sales within the city mean city residents are consuming less sugar. The correct answer undermines this assumption by providing a highly plausible alternative explanation: the tax merely caused residents to drive just outside the city limits to buy their beverages. If total consumption remains roughly the same, the conclusion that the tax improved public health falls apart.

Step-by-Step Solution

1
Identify the conclusion of the argument.
The conclusion is: 'Our new municipal tax on sugary beverages... has been a resounding success in improving public health.'
Understanding the exact claim being made is necessary to know what needs to be undermined.
2
Identify the premise supporting the conclusion.
The premise is: 'The total volume of sugary beverages sold within the city limits has decreased by 20% since the tax was introduced.'
This shows the evidence the author uses to justify their claim.
3
Identify the logical gap between the premise and the conclusion.
The author assumes that a decrease in sales *within the city limits* directly equates to a decrease in overall consumption by city residents, which would lead to improved health.
Finding the assumption reveals the argument's vulnerability.
4
Evaluate the answer choices to find the one that exploits this gap.
The option showing a matching surge in sales just outside the city limits proves that consumption did not drop; the location of purchase simply shifted. This severs the link between the premise and the conclusion.
A valid 'weaken' answer must show that the conclusion is unlikely to be true even if the premises are true.

Key Concept

Evaluating Alternate Explanations / Assessing the Scope of Evidence
Question 3Question →

Match each of the following arguments (1-4) with the newly discovered fact that most seriously undermines its reasoning.

Click a left item, then click its matching right item

Items

Following the installation of a new synchronized traffic light system across the city, the number of intersection collisions decreased by 20 percent. Therefore, the synchronized lights directly caused our roads to become safer.
A recent survey of customers at the Greenfield Health Cooperative showed that over 90 percent strongly prefer almond milk to dairy milk. This demonstrates that a vast majority of the city's overall population prefers plant-based milk alternatives.
Over the past year, the survival rate for cardiac surgery patients at Mercy Hospital was significantly lower than the survival rate for cardiac surgery patients at County General. Clearly, County General employs more competent surgical staff.
The neighboring nation of Corto experienced rapid economic growth immediately after replacing its progressive tax system with a flat tax. Consequently, implementing a flat tax in our nation will similarly stimulate rapid economic expansion.

Matches

Show answer & explanation

Answer

Argument 1 (Traffic System) pairs with the intersection closures; Argument 2 (Survey) pairs with the vegan clientele; Argument 3 (Hospitals) pairs with the severe cases; Argument 4 (Tax Policy) pairs with the differing economies.
Each correct match directly exploits the specific logical flaw present in its corresponding argument. The traffic argument is weakened by an alternate cause. The survey argument is weakened by demonstrating sample bias. The hospital comparison is weakened by showing an unequal baseline. The tax policy analogy is weakened by pointing out a fundamental difference between the two entities.

Step-by-Step Solution

1
Analyze the first argument (Traffic System) to find the logical gap.
The argument assumes a causal relationship based on a temporal correlation, ignoring potential alternate causes.
Identifying the specific flaw is required to find evidence that presents an alternate explanation.
2
Match the first argument to the counter-evidence.
The fact that dangerous intersections were closed for construction provides an alternate cause for the drop in collisions.
An alternate cause breaks the assumed causal link.
3
Analyze the second argument (Survey) and find the logical gap.
The argument relies on an unrepresentative sample, generalizing from shoppers at a specific health store to the entire city.
Recognizing a sampling flaw directs the search toward evidence that the sample is biased.
4
Match the second argument to the counter-evidence.
The evidence that the store targets vegans shows the sample is heavily biased.
Evidence of sample bias invalidates generalizations drawn from that sample.
5
Analyze the third argument (Hospitals) and match to counter-evidence.
The argument compares survival rates unfairly. The evidence that Mercy Hospital takes the most severe cases explains the lower survival rate independently of surgeon competence.
Finding an omitted variable (patient severity) destroys the unfair comparison.
6
Analyze the fourth argument (Tax Policy) and match to counter-evidence.
The argument relies on a faulty analogy. The evidence showing their economies are fundamentally different attacks the basis of the analogy.
Highlighting relevant differences between compared entities is the primary way to weaken an analogy.

Key Concept

Evaluating argument structures and identifying the evidence that exposes logical vulnerabilities such as alternate causes, biased samples, unequal comparisons, and faulty analogies.
Question 4Question →

Historian: In the mid-14th century, settlements in the Variscan Highlands that had recently adopted the 'deep-furrow' agricultural method experienced a 40 percent greater population decline during the regional famine than neighboring Variscan settlements that retained traditional shallow tilling. Therefore, the deep-furrow method was likely more susceptible to the severe drought that caused the famine, leading to more catastrophic crop yields and higher starvation rates in the settlements that used it.

Which of the following, if true, most seriously weakens the historian's argument?

Show answer & explanation

Answer: The wealth accumulated from the high crop yields of the deep-furrow method during normal years allowed residents of those settlements to afford passage to unaffected regions when the drought struck.

Answer

The option stating that the wealth from the deep-furrow method allowed residents to afford passage to unaffected regions.
The historian's argument relies on a flawed causal assumption: that the observed population decline in deep-furrow settlements was necessarily caused by an increase in mortality (starvation) resulting from crop failure. This correct answer introduces a devastating alternate explanation for the demographic shift. If the residents used surplus wealth generated by the deep-furrow method to relocate away from the famine zone, the population decline was caused by voluntary migration, not starvation. Furthermore, this implies the agricultural method was actually highly successful, directly contradicting the conclusion that it was an operational failure.

Step-by-Step Solution

1
Identify the conclusion of the argument.
The deep-furrow method was more susceptible to the drought, leading to worse crop yields and higher starvation rates.
Understanding the exact claim being made is necessary to evaluate its structural vulnerabilities.
2
Identify the premise supporting this conclusion.
Deep-furrow settlements experienced a 40 percent greater population decline during the famine compared to traditional settlements.
The argument relies entirely on a direct causal link between this statistical premise and the conclusion.
3
Locate the logical gap or assumption.
The historian equates 'population decline' solely with 'starvation rates', failing to consider other mechanisms of demographic change such as migration.
Identifying unstated assumptions is the primary method for finding the central flaw in causal reasoning.
4
Evaluate the options to find one that exploits this gap.
The correct option provides a compelling alternate cause for the population decline: mass emigration made possible by the economic success of the deep-furrow method itself.
An alternate cause that completely severs the link between the agricultural method's purported failure and the population drop fatally undermines the conclusion.

Key Concept

Causal Reasoning and Alternate Explanations
Question 5Question →

Botanist: The traditional view among ecologists is that the rapid decline of the indigenous Luminis plant population in the valley was caused by an influx of herbivorous beetles. However, recent field data reveals that during the five years immediately preceding the plant's near-extinction, the plants significantly decreased their production of toxic alkaloids—their primary natural defense against the beetles. If the beetles were truly the primary threat, the plants would have evolved to increase, rather than decrease, their alkaloid production. Therefore, the decline of the Luminis plant must have been caused by a different environmental factor, such as nutrient depletion in the soil.

Which one of the following, if true, most weakens the botanist's argument?

Show answer & explanation

Answer: The herbivorous beetles recently developed a unique physiological reliance on the Luminis plant's toxic alkaloids, leading them to selectively target and devour only those plants with high alkaloid levels.

Answer

The correct answer states that the herbivorous beetles evolved a reliance on the alkaloids, selectively devouring plants with high alkaloid levels.
The correct answer undermines the botanist's argument by providing an alternative, counter-intuitive explanation for the premise. The botanist assumes that a decrease in defensive alkaloids means the beetles were not a threat. However, if the beetles evolved to specifically target and consume plants with high alkaloid levels, then possessing those alkaloids became a deadly disadvantage. In this scenario, the plant population would naturally evolve to produce fewer alkaloids precisely because the beetles were the primary threat. This completely destroys the botanist's assumption and supports the traditional view that the beetles caused the decline.

Step-by-Step Solution

1
Identify the core conclusion of the argument.
The botanist concludes that the decline of the Luminis plant was caused by an environmental factor (like nutrient depletion), not by the herbivorous beetles.
Evaluating any argument requires strictly defining the specific point the author is attempting to prove.
2
Identify the primary premise and the underlying assumption.
The premise is that the plants decreased their production of defensive toxic alkaloids. The assumption is that if beetles were the main threat, evolutionary pressure would force the plants to increase, not decrease, this defense.
Weakening an argument usually requires identifying and attacking the unstated assumption linking the premise to the conclusion.
3
Determine the criteria for a correct weakener.
A correct answer must provide a reason why the beetle threat would actually CAUSE the plants to decrease their alkaloid defense.
By explaining the premise in a way that points back to the beetles as the threat, you dismantle the author's logic completely.
4
Evaluate the options against this criterion.
The option showing that beetles selectively eat plants with high alkaloids perfectly explains why alkaloid production dropped—it was an evolutionary response to avoid the beetles.
This directly attacks the botanist's assumption and re-establishes the traditional view.

Key Concept

Argument Evaluation: Weaken (Alternate Explanation for Evidence)
Question 6Question →

Match each argument with the piece of new evidence that most effectively weakens its conclusion. Assume all evidence statements are true.

Click a left item, then click its matching right item

Items

Excavations at the ancient site of Kaelen yielded hundreds of bronze swords but no bronze agricultural tools. Historians conclude that the Kaelen people were primarily a warrior society that did not engage in farming.
In the year following the introduction of a premium loyalty program, a supermarket chain saw its total sales volume increase by 15%. Executives concluded that the new program successfully attracted a broader customer base.
One year after a corporate wellness initiative mandated ergonomic chairs, employee reports of chronic back pain rose by 25%. Management concluded that the new ergonomic chairs must be physically harmful.
A municipality deemed its recycling campaign a failure, noting that the percentage of total municipal waste successfully recycled fell from 30% to 22% over the campaign's duration. They concluded residents are recycling a smaller absolute amount of material.

Matches

Show answer & explanation

Answer

Argument 1 matches with the soil composition evidence. Argument 2 matches with the bankrupt competitors evidence. Argument 3 matches with the digital portal evidence. Argument 4 matches with the commercial waste expansion evidence.
Each correct pairing directly attacks the specific logical vulnerability in the argument's inferential leap without contradicting the stated premises. The soil preservation bias explains the missing tools; the closed competitors provide an alternate cause for the sales bump; the new portal explains the increased reports independently of actual pain; and the massive increase in total waste demonstrates how the recycling percentage could drop while the absolute amount recycled remained constant or increased.

Step-by-Step Solution

1
Analyze Argument 1 (Kaelen excavations)
Identify the flaw: concluding a lack of activity from an absence of evidence in the archaeological record.
Finding an alternative explanation for why the tools didn't survive perfectly attacks this gap.
2
Analyze Argument 2 (Supermarket loyalty program)
Identify the flaw: Correlation vs. Causation. The argument assumes the program caused the sales increase.
Finding an alternate cause for the sales bump (competitors closing) severs the causal link.
3
Analyze Argument 3 (Ergonomic chairs)
Identify the flaw: confusing an increase in reports of a problem with an increase in the actual incidence of the problem.
Evidence showing that reporting became easier explains the rise in reports without validating the chairs' harm.
4
Analyze Argument 4 (Recycling percentages)
Identify the flaw: Percentage vs. Number. A drop in percentage does not guarantee a drop in the absolute amount if the overall total increased.
Evidence showing the total waste denominator artificially inflated proves the absolute amount of recycling didn't necessarily drop.
5
Evaluate the remaining distractor evidence
Identify that the evidence regarding auditor data errors attacks the premises directly.
In standard logical reasoning evaluation, effectively weakening an argument requires accepting the premises as true and attacking the inferential leap, making this a classic trap.

Key Concept

Identifying and exploiting specific logical gaps (Alternative Explanations, Causal Flaws, Reporting Bias, and Percentage vs. Number errors) to undermine an argument's conclusion.
Question 7Question →

Match each brief argument with the specific piece of new evidence that most effectively weakens its conclusion.

Click a left item, then click its matching right item

Items

A university study found that students who take notes by hand score higher on exams than those who type. Thus, handwriting notes causes better academic performance.
After the regional government introduced a subsidy for solar panels, carbon emissions dropped by 15%. This proves the subsidy was highly effective.
A poll at a tech industry conference revealed that 85% of attendees believe AI will create jobs. Therefore, the general public is optimistic about AI.
Over the last five years, workplace accidents involving robotic arms have tripled, while accidents involving human workers decreased. Clearly, robotic arms are becoming less safe.

Matches

Show answer & explanation

Answer

Argument 1 matches Evidence C. Argument 2 matches Evidence A. Argument 3 matches Evidence D. Argument 4 matches Evidence B.
Each correct pairing effectively targets the specific logical vulnerability in the corresponding argument: Argument 1 is weakened by an alternate cause for a correlation; Argument 2 is weakened by an independent alternate cause for an outcome; Argument 3 is weakened by exposing sample bias; and Argument 4 is weakened by providing context on population size changes (base rate).

Step-by-Step Solution

1
Analyze Argument 1 (Note-taking)
Identified a correlation-to-causation flaw. Look for evidence providing an alternate explanation for the correlation.
Evidence C shows that the motivation level of the students is the true cause of the higher scores, not the physical act of note-taking.
2
Analyze Argument 2 (Solar subsidy)
Identified a chronological correlation assumed to be causal. Look for an alternate cause for the emissions drop.
Evidence A provides a strong alternate cause: a decline in manufacturing due to a recession, weakening the claim that the subsidy was responsible.
3
Analyze Argument 3 (AI poll)
Identified a sampling flaw. The sample (tech attendees) is not representative of the conclusion's target group (the general public).
Evidence D highlights why this specific sample is inherently biased compared to the general public, destroying the argument's validity.
4
Analyze Argument 4 (Robotic accidents)
Identified a numbers vs. proportions flaw. An absolute increase in accidents doesn't mean safety decreased if usage also increased massively.
Evidence B shows the number of robots increased drastically, which naturally leads to more total accidents even if the rate of accidents per robot remained safe or improved.

Key Concept

Identifying and targeting specific logical vulnerabilities (causation errors, unrepresentative samples, and base rate neglect) to weaken arguments.
Question 8Question →

For each argumentative claim presented on the left, identify the factual statement on the right that most severely undermines its conclusion.

Click a left item, then click its matching right item

Items

An analysis of regional healthcare data indicates that patients recovering from joint surgery at Apex Clinic have shorter hospital stays than those at Zenith Hospital. Thus, Apex Clinic's surgical techniques must be superior.
Following the enactment of a municipal recycling mandate, the volume of refuse processed at the county incinerator dropped by twenty percent. It is evident that the mandate successfully minimized the amount of garbage residents generate.
Archaeological digs at the ancient city of Oakhaven revealed that grain storage silos built in the twelfth century are substantially smaller than those built in the tenth century. This suggests that Oakhaven's agricultural output declined over those two centuries.
Over the last quarter, the local bookstore 'Folio & Spine' saw a sharp increase in revenue immediately after they began hosting weekly author readings. Therefore, the author readings are driving the bookstore's financial success.

Matches

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Answer

The Apex Clinic argument matches with the admission policy statement; the recycling mandate argument matches with the manufacturing plant closure; the Oakhaven silos argument matches with the denser storage techniques; and the bookstore argument matches with the closure of the competing retailer.
Each correct match successfully targets the logical gap in the respective argument. The healthcare argument suffers from a flawed comparison (selection bias), which is exposed by the clinic's admission policy. The recycling argument shifts scope from total refuse to residential garbage, which is undermined by the factory closure. The archaeological argument assumes a direct volume-to-yield ratio, which is weakened by the denser storage fact. The bookstore argument commits a post hoc fallacy, which is undermined by the closure of a competitor providing an alternate cause for increased revenue.

Step-by-Step Solution

1
Analyze the healthcare argument.
Identified the conclusion (surgical techniques are superior) and the premise (shorter hospital stays).
To weaken the argument, we must find a statement showing the patient populations differ in a way that affects recovery times, which points to the admission policy statement.
2
Analyze the municipal recycling argument.
Identified the conclusion (mandate minimized resident garbage) based on the premise (a 20% total drop at the incinerator).
To weaken, we need an alternate source for the total drop that has nothing to do with residents, pointing to the closure of the manufacturing plant.
3
Analyze the archaeological argument about silos.
Identified the conclusion (agricultural output declined) based on the premise (silos are smaller).
To weaken, we must find a reason why silos would be smaller even if agricultural yield remained steady, pointing to the denser storage techniques.
4
Analyze the bookstore revenue argument.
Identified the causal claim (author readings drive success) based on temporal correlation.
To weaken a causal claim based on correlation, we must find an alternate cause for the revenue increase, pointing to the closure of the competitor.

Key Concept

Identifying unstated assumptions and evaluating alternative explanations to weaken causal or comparative arguments.
Question 9Question →

The following exercise presents four short arguments on various topics. For each argument, select the single piece of newly discovered information that exposes its most significant logical vulnerability and weakens its conclusion.

Click a left item, then click its matching right item

Items

Archaeologist: A newly discovered ancient desert settlement contains thousands of fish bones. Thus, this arid region must have featured a large freshwater lake during the era the settlement was occupied.
Cafe Owner: Since we switched to a less expensive brand of coffee beans, our weekly sales revenue has dropped by 15%15\%. Clearly, our customers dislike the taste of the new coffee and are consequently purchasing less.
Biologist: A certain species of tree frog has vibrant blue skin. Since most brightly colored amphibians are highly venomous, this frog's coloration must serve as a warning to predators about its toxicity.
Manager: We introduced a new productivity application intended to help employees complete tasks faster. A month later, employees logged the exact same number of total working hours as before. Thus, the application did not increase employee productivity.

Matches

Show answer & explanation

Answer

The archaeological argument matches the fact about coastal trading networks. The business argument matches the fact about municipal utility work blocking access. The biological argument matches the fact about the absence of toxin-synthesizing insects. The tech management argument matches the fact about the massive new client increasing workload.
Each correct pairing successfully introduces a fact that attacks the unstated assumption of its respective argument. The trade fact provides an alternative source for the fish, the construction provides an alternative cause for lost revenue, the biological fact removes the mechanism for toxicity, and the workload fact proves productivity actually increased despite flat hours.

Step-by-Step Solution

1
Identify the conclusion and the supporting premise for each argument.
Isolated four distinct logical gaps: assuming local origin of artifacts, assuming a single cause for a revenue drop, assuming toxicity from coloration, and conflating flat work hours with flat productivity.
To weaken an argument, one must first locate the gap or assumption between the evidence provided and the conclusion drawn.
2
Evaluate the counter-evidence to find alternative explanations or facts that directly attack these specific assumptions.
The trade fact attacks local origin. The construction fact attacks the revenue cause. The diet fact attacks actual toxicity. The workload fact re-contextualizes the flat work hours.
The correct weakener will specifically exploit the vulnerability of its target argument without relying on unwarranted outside assumptions.
3
Pair the arguments with their corresponding weakeners.
All four pairs are logically matched.
Confirming that each piece of evidence uniquely and effectively undermines its specific target argument.

Key Concept

Identifying alternative causal explanations and recognizing when arguments rely on flawed assumptions to bridge premises and conclusions.
Question 10Question →

Marine Biologist: The accelerated structural degradation of the deep-water coral Lophelia pertusa in the Boreal Basin over the last twenty years is widely attributed to oceanic acidification. Proponents of this theory argue that higher acidity depletes the dissolved calcium carbonate that the corals extract from the water to build their skeletons. However, recent hydrographic surveys demonstrate that the overall concentration of dissolved calcium carbonate in the Boreal Basin has actually risen by nearly twelve percent over this exact timeframe. Clearly, the degradation of the coral's structure is not a consequence of oceanic acidification, but must stem from a different environmental stressor, such as the recently documented increase in deep-sea trawling.

Statement: If true, the fact that the recent twelve percent increase in dissolved calcium carbonate in the Boreal Basin consists entirely of aragonite—the specific crystalline form of calcium carbonate that constitutes the existing skeletons of Lophelia pertusa and which dissolves rapidly when exposed to higher acidity—weakens the marine biologist's argument.

Show answer & explanation

Answer: True

Answer

The statement is True. The newly introduced fact actively undermines the marine biologist's conclusion by demonstrating that the increased calcium carbonate is actually a symptom of the acidification destroying the coral.
The assertion is true because the newly introduced fact provides a devastating alternate interpretation of the biologist's evidence. The biologist assumes that the twelve percent increase in dissolved calcium carbonate means the environment is hospitable and that acidification isn't starving the coral. However, the new fact reveals that this increase is actually the dissolved remains of the corals' own skeletons. This causal inversion completely destroys the biologist's conclusion by demonstrating that acidification is indeed the direct cause of the degradation, making the statement a powerful weakener.

Step-by-Step Solution

1
Analyze the argument's core structure to identify the premise and conclusion.
Premise: Dissolved calcium carbonate has risen by twelve percent. Conclusion: Acidification is not causing the coral degradation; a different stressor is responsible.
Isolating the argument's logical core is necessary to identify its structural vulnerabilities.
2
Identify the underlying assumption bridging the premise and the conclusion.
The biologist assumes that an increase in dissolved calcium carbonate means the environment has an abundance of resources for the coral, implying that the corals are safe from the resource depletion normally caused by acidification.
Weakening an argument at the highest level of difficulty almost always requires attacking an unstated, flawed assumption.
3
Apply the new statement's evidence to the biologist's assumption.
The statement reveals that the twelve percent increase is composed of aragonite, which is actively dissolving off the corals' own skeletons as a direct result of higher acidity.
This establishes a causal inversion. The premise (higher carbonate) is not proof of the coral's safety; it is the chemical footprint of the coral being actively destroyed by the exact cause the author prematurely dismissed.

Key Concept

Evaluating alternate causes and recognizing causal inversions where evidence intended to disprove a phenomenon actually serves as a direct symptom of it.
Question 11Question →

Analyze the four arguments below. Match each argument (Left) to the specific piece of new evidence (Right) that most severely weakens its conclusion by exposing its underlying logical flaw.

Click a left item, then click its matching right item

Items

Paleontologist: The extinction of the large flightless birds in this region was almost certainly driven by the arrival of early human settlers. Fossil evidence demonstrates a rapid collapse in the bird population that perfectly coincides with the earliest known human encampments in the valley.
Financial Analyst: To maximize long-term profitability, our corporation must immediately transition to an open-allocation management structure. A comprehensive industry review shows that 85% of the most highly profitable tech companies currently utilize an open-allocation framework.
School Board Administrator: The new intensive tutoring program is clearly working to improve overall math proficiency. In the district where it was implemented, the absolute number of students failing the standardized math assessment plummeted by nearly 50% this year.
Medical Researcher: The new synthetic-polymer heart valve is more effective than the traditional mechanical valve. Clinical surveys show that patients who received the synthetic valve experienced a significantly lower rate of post-surgical complications and faster recovery times.

Matches

Show answer & explanation

Answer

The Paleontologist argument matches the climatic shift evidence (exposing a third-variable cause). The Financial Analyst argument matches the capital baseline evidence (exposing reverse causation). The School Board argument matches the population exodus evidence (exposing a numbers vs. percentages flaw). The Medical Researcher argument matches the younger patients evidence (exposing selection bias).
Each correct pairing perfectly exploits the specific logical gap in the stimulus. The climate shift introduces a common cause for the paleontological correlation. The capital requirement introduces reverse causation for the financial correlation. The population drop attacks the numerical basis of the educational claim. The surgical instructions expose a fatal selection bias in the medical claim.

Step-by-Step Solution

1
Analyze the Paleontologist argument for its logical gap.
Identified a correlation-to-causation flaw based on simultaneous occurrences.
Finding an alternate cause or a third factor that causes both events is the standard way to weaken this type of causal claim.
2
Analyze the Financial Analyst argument.
Identified a correlation between a management structure and profitability.
Since the evidence is just a cross-sectional snapshot (highly profitable companies have this structure), it is vulnerable to reverse causation—they might have the structure because they are profitable.
3
Analyze the School Board Administrator argument.
Identified a claim of improved proficiency based solely on a drop in the absolute number of failures.
Absolute numbers cannot prove a change in rate or quality without knowing the total base size. A change in the base population is the most direct weakener.
4
Analyze the Medical Researcher argument.
Identified an observational comparison between two groups of patients with different treatments.
Without a randomized controlled trial, the groups might not be equivalent. Pointing out a pre-existing advantage in one group (selection bias) destroys the conclusion that the treatment itself caused the better outcome.

Key Concept

Identifying and attacking specific structural flaws in causal reasoning, statistical evidence, and observational comparisons.
Question 12Question →

Historian: The rapid population growth in the Aethelian Valley during the 11th century was almost certainly driven by the introduction of the heavy iron plow. Prior to its introduction in 1012, the valley's population had been stagnant for over two centuries. By 1050, the population had nearly doubled. The heavy plow allowed farmers to cultivate the dense, clay-rich soils of the valley floor, significantly increasing the total agricultural yield and thus supporting a much larger population.

Which of the following, if true, most seriously weakens the historian's argument?

Show answer & explanation

Answer: In 1012, a devastating conflict in a neighboring kingdom caused a massive influx of refugees to permanently resettle in the Aethelian Valley, bringing the heavy plow technology with them.

Answer

The statement detailing a massive influx of refugees in 1012 who brought the plow with them most seriously weakens the argument.
This option weakens the argument by introducing a compelling third variable: a massive influx of refugees. If tens of thousands of refugees settled in the valley in 1012, this immigration wave serves as a more direct alternative cause for the population doubling by 1050. Furthermore, because these refugees brought the plow with them, it explains why the plow's arrival correlated perfectly with the population boom, completely dismantling the historian's claim that the plow itself drove the population growth via agricultural yield.

Step-by-Step Solution

1
Analyze the stimulus to identify the core argument structure.
Conclusion: The heavy iron plow caused the rapid population growth. Premises: Population was stagnant before the plow's arrival in 1012; population doubled by 1050; the plow increased agricultural yield.
Understanding the causal claim is necessary to evaluate which piece of new evidence would most effectively undermine it.
2
Identify the primary vulnerability in the historian's reasoning.
The historian assumes that because the plow's introduction preceded the population growth, it must have caused it (correlation to causation).
Recognizing a causal flaw directs the search for an answer choice that provides an alternative cause, reverse causation, or a third variable.
3
Evaluate the answer choices against the identified vulnerability.
The correct option reveals that an influx of refugees concurrently caused the population jump and introduced the plow, severing the historian's causal link.
An effective alternative cause must comprehensively explain the observed phenomenon without relying on the author's stated mechanism.

Key Concept

Weakening Causal Arguments
Estimated Time:2m 0s
Question 13Question →

Ornithologist: A recent study found that urban crows living in close proximity to fast-food restaurants have significantly higher average body weights than crows living in rural habitats. The diet of these urban crows consists heavily of discarded processed foods, which are notoriously high in calories. Therefore, it is clear that the consumption of these high-calorie processed foods is the primary cause of the increased body weight in these urban crows.

Which of the following, if true, most seriously weakens the ornithologist's argument?

Show answer & explanation

Answer: Due to the high concentration of readily available food, urban crows near fast-food restaurants expend significantly fewer calories daily flying and foraging than rural crows do.

Answer

The option stating that urban crows near fast-food restaurants expend significantly fewer calories daily flying and foraging than rural crows do.
The argument concludes that a high-calorie diet is the primary cause of the urban crows' higher body weight. However, body weight depends on both caloric intake and caloric expenditure. By pointing out that these urban crows expend significantly fewer calories because their food is highly concentrated, this statement introduces a compelling alternate explanation for their increased weight. This severs the assumed direct link between the high-calorie food itself and the weight gain, thereby severely weakening the conclusion.

Step-by-Step Solution

1
Identify the argument's premises and main conclusion.
Premises: Urban crows near fast food weigh more than rural crows, and they eat a high-calorie processed diet. Conclusion: The high-calorie diet causes the increased body weight.
Deconstructing the argument is necessary to spot the logical gap.
2
Determine the type of reasoning and its inherent vulnerabilities.
The argument uses causal reasoning based on a correlation. A vulnerability is that there might be an alternate cause for the effect (increased body weight).
Understanding the flaw type directs the search for the correct weakening statement.
3
Evaluate the options to find the one that exploits this vulnerability.
The correct option points out that urban crows burn fewer calories. Since weight is determined by calories in minus calories out, a lower expenditure of calories is a plausible alternate explanation for the higher weight.
Introducing a viable alternate explanation is the standard method for weakening a causal argument on the LSAT.

Key Concept

Weakening causal arguments by identifying alternate explanations
Question 14Question →

Human Resources Director: Six months ago, our company replaced its open-plan office layout with private cubicles in an effort to boost employee productivity. Recent observational data reveals that employees are currently spending 30 percent less time engaging in casual conversations in the office corridors than they did before the renovation. Clearly, the transition to private cubicles has successfully increased overall worker productivity by reducing social distractions.

Which one of the following, if true, most seriously weakens the human resources director's argument?

Show answer & explanation

Answer: The company's most innovative and profitable projects typically emerge from ideas generated during spontaneous, casual conversations in common areas.

Answer

The statement that the company's most innovative and profitable projects typically emerge from ideas generated during spontaneous, casual conversations in common areas.
This statement directly attacks the core assumption in the human resources director's argument. The director assumes that less time spent in casual corridor conversations equates to fewer 'social distractions' and therefore higher productivity. However, if these casual conversations are actually the source of the company's most innovative and profitable projects, then a 30 percent reduction in these conversations would likely damage the company's productivity. This severs the logical connection between the premise (less corridor chatting) and the conclusion (increased productivity).

Step-by-Step Solution

1
Identify the main conclusion of the argument.
The conclusion is that the transition to private cubicles has increased overall worker productivity by reducing social distractions.
To evaluate or weaken an argument, you must first isolate the exact claim the author is attempting to prove.
2
Identify the premise provided in support of the conclusion.
The premise is that employees are spending 30 percent less time engaging in casual corridor conversations since the cubicles were installed.
Understanding the evidence highlights the gap between what is explicitly stated and what is concluded.
3
Find the logical gap or unstated assumption in the reasoning.
The director assumes that 'casual conversations in the corridors' are strictly unproductive 'social distractions' that hinder work.
Identifying the assumption reveals the argument's vulnerability.
4
Select the option that attacks this assumption.
The correct option demonstrates that these casual conversations are actually highly productive because they lead to profitable and innovative projects.
By showing that the supposed 'distraction' is actually a driver of productivity, the link between the premise and the conclusion is severed, severely weakening the argument.

Key Concept

Argument Evaluation: Weakening an Argument by Attacking an Unstated Assumption
Question 15Question →

Nutritionist: Residents of the mountainous region of Vargia consume an unusually high amount of the local root vegetable kalian, and they also boast the lowest rates of heart disease in the country. To combat rising rates of heart disease nationwide, the government should subsidize the cultivation of kalian and promote its consumption among the general population.

Which one of the following, if true, most weakens the nutritionist's argument?

Show answer & explanation

Answer: The steep, rugged terrain of Vargia requires its residents to engage in intense daily physical exertion, a lifestyle factor known to drastically reduce the risk of heart disease.

Answer

The correct answer is the option stating that the steep, rugged terrain of Vargia requires intense daily physical exertion, which drastically reduces the risk of heart disease.
The argument relies on a correlation between kalian consumption and low heart disease rates to conclude that kalian causes heart health. The correct answer introduces a highly plausible alternative cause (intense physical exertion due to terrain) for the low heart disease rates in Vargia. This alternate explanation severs the assumed causal link, making it much less likely that promoting kalian nationwide will have the desired effect.

Step-by-Step Solution

1
Identify the argument's premises and conclusion.
Premises: Vargians eat lots of kalian AND have the lowest rates of heart disease. Conclusion: Promoting kalian nationwide will combat rising heart disease rates.
Deconstructing the argument is necessary to evaluate the logical leap being made.
2
Analyze the logical gap (flaw) between the premises and the conclusion.
The nutritionist assumes a causal relationship (kalian prevents heart disease) based solely on a correlation in Vargia.
Identifying the flaw helps predict what type of information would most effectively weaken the argument.
3
Evaluate the answer choices to find the one that exploits this logical gap.
The option about Vargia's rugged terrain introduces an alternative cause (physical exertion) for the low heart disease rates, destroying the assumed causal link to kalian.
A valid weaken answer typically introduces new information that makes the conclusion less likely to follow from the premises.

Key Concept

Alternative Explanations in Causal Arguments
Estimated Time:1m 30s
Question 16Question →

Argument: Last year, the Sunnyvale City Council launched a public awareness campaign promoting the health benefits of eating locally grown produce. Over the past twelve months, the sales of locally grown produce at Sunnyvale farmers' markets have doubled. The city council concludes that their public awareness campaign successfully persuaded residents to buy more local produce.

Statement: The new fact that a massive nationwide shortage of non-local produce drastically increased the prices of imported vegetables over the last twelve months actively weakens the city council's conclusion.

Show answer & explanation

Answer: True

Answer

True
The factual assertion is true. The argument relies on a causal link between the awareness campaign and the increase in sales. By introducing a different, highly practical economic reason for people to buy local produce (imported produce became too expensive), the new fact provides a strong alternative explanation for the observed phenomenon. This directly undermines the conclusion that the campaign was the driving force behind the increased sales.

Step-by-Step Solution

1
Identify the argument's premises and conclusion.
Premise: Campaign launched, local produce sales doubled. Conclusion: The campaign caused the increase in sales.
Understanding the exact causal claim is necessary to evaluate whether it can be weakened.
2
Analyze the logical gap in the argument.
The argument assumes that because the campaign preceded the increase in sales, it must have caused the increase, ignoring other potential economic or environmental factors.
Weakening an argument usually involves exploiting its logical gap, such as a jump from correlation to causation.
3
Evaluate the impact of the new factual assertion on the argument's conclusion.
The new fact introduces a competing cause for the increased sales: high prices of alternative (imported) produce. This makes the campaign less likely to be the actual cause.
To determine if the statement is true, we must verify if the new fact actively undermines the causal relationship claimed in the conclusion.

Key Concept

Identifying alternative causes to weaken causal conclusions.
Question 17Question →

Nutritionist: The new energy bar, PowerBite, consists of 25% pure whey protein, whereas our current best-selling bar, MaxEnergy, consists of only 15% whey protein. Since whey protein is the primary driver of muscle recovery after strenuous workouts, athletes looking to maximize their muscle recovery should immediately switch from eating MaxEnergy bars to eating PowerBite bars.

Which of the following, if true, most seriously weakens the nutritionist's argument?

Show answer & explanation

Answer: A single MaxEnergy bar weighs three times as much as a single PowerBite bar.

Answer

The option stating that a single MaxEnergy bar weighs three times as much as a single PowerBite bar.
The nutritionist's argument relies on a classic 'percentage versus amount' flaw. The argument assumes that because PowerBite has a higher concentration of protein (25% compared to 15%), it will deliver more total protein to the athlete. However, if a MaxEnergy bar is three times larger than a PowerBite bar, an athlete eating one MaxEnergy bar will consume significantly more total whey protein than they would by eating one PowerBite bar. Because switching to PowerBite would actually decrease their total protein intake, this fact completely undermines the conclusion that switching will maximize recovery.

Step-by-Step Solution

1
Identify the main conclusion of the argument.
Athletes looking to maximize muscle recovery should switch from MaxEnergy to PowerBite.
This is the ultimate recommendation the nutritionist is trying to prove.
2
Identify the premises supporting this conclusion.
PowerBite is 25% protein, MaxEnergy is 15% protein, and protein drives muscle recovery.
These are the facts provided to justify the recommendation.
3
Find the logical gap between the premises and the conclusion.
The nutritionist confuses a proportion (percentage of protein) with an absolute quantity (total grams of protein).
A higher percentage does not guarantee a higher total amount if the overall sizes of the items being compared are different.
4
Select the option that exploits this logical gap.
The option stating MaxEnergy weighs three times as much directly addresses this gap.
If MaxEnergy is three times larger, 15% of its large weight provides more total protein than 25% of PowerBite's small weight, proving athletes would actually get less protein by switching.

Key Concept

Differentiating between proportions/percentages and absolute quantities in arguments.
Estimated Time:1m 0s
Question 18Question →

Match each argument below to the piece of new evidence that most directly weakens its conclusion.

Click a left item, then click its matching right item

Items

Mayor Smith's popularity must be declining because attendance at her town hall meetings is much lower this year.
City roads are more dangerous than rural roads because a significantly larger total number of car accidents happen in the city.
The new gym will be highly profitable because it is opening right next to a busy organic grocery store.
The herbal tea cures insomnia, as all participants in a recent study reported better sleep after drinking it for a week.

Matches

Show answer & explanation

Answer

Mayor Smith matches to online broadcasts; City roads match to more miles driven; New gym matches to outdoor preference; Herbal tea matches to prescription medication.
Each correct match directly exploits a specific logical flaw in the argument's reasoning. By introducing alternate explanations, distinguishing totals from rates, attacking unwarranted business assumptions, or introducing confounding variables, the new evidence demonstrates that the original conclusions do not necessarily follow from their premises.

Step-by-Step Solution

1
Analyze the argument regarding Mayor Smith's popularity.
The argument assumes that low physical attendance at meetings definitively proves low popularity.
Identifying the unstated assumption is the first step to finding a weakness.
2
Find the evidence that provides an alternative reason for the low attendance.
The fact that meetings are now broadcast online explains the low physical attendance without requiring a drop in popularity.
An alternate explanation successfully weakens a correlative claim.
3
Analyze the argument regarding city roads and find the structural flaw.
The argument confuses a high total number of accidents with a higher rate of danger. The evidence that city drivers drive millions more miles addresses this total vs. rate flaw.
Understanding the difference between absolute numbers and proportions is crucial to weakening statistical arguments.
4
Analyze the gym and herbal tea arguments to find their respective weakening evidence.
The gym argument is weakened by evidence that the adjacent store's customers dislike indoor gyms. The tea argument is weakened by the introduction of an alternate cause (prescription medication).
Each piece of correct evidence successfully severs the assumed logical link between the given premises and the final conclusions.

Key Concept

Evaluating Arguments: Weakening
Question 19Question →

City Council Member: Last month, we installed a new, synchronized traffic light system at the Oak Street intersection. This month, the number of traffic accidents at that intersection dropped by 30% compared to the previous month. Therefore, the new traffic light system has clearly improved safety by reducing accidents at the Oak Street intersection.

Which of the following, if true, most seriously weakens the city council member's argument?

Show answer & explanation

Answer: During the same month, major roadwork closed the primary highway feeding into the Oak Street intersection, drastically reducing the volume of traffic passing through it.

Answer

The statement regarding major roadwork closing the primary highway and reducing traffic volume.
The argument relies on a flawed causal assumption: because the drop in accidents followed the installation of the traffic lights, the lights must have caused the drop. To weaken a causal argument, you should look for an alternate cause for the observed effect. The correct answer provides a perfect alternate cause: if major roadwork prevented cars from entering the intersection, the number of accidents would naturally decrease, completely independently of the new traffic light system.

Step-by-Step Solution

1
Identify the conclusion of the argument.
The conclusion is that the new traffic light system has improved safety by reducing accidents at the Oak Street intersection.
Understanding what the author is trying to prove is the first step in evaluating any argument.
2
Identify the premises supporting the conclusion.
The premise is that a new traffic light system was installed last month, and this month, accidents at that intersection dropped by 30%.
Premises represent the evidence used to justify the conclusion.
3
Analyze the logical gap between the premises and the conclusion.
The argument assumes a causal relationship based merely on a sequence of events. It assumes no other factors could have caused the 30% drop in accidents.
Finding the assumption or logical flaw reveals how the argument can be weakened.
4
Evaluate the options to find one that exploits this gap.
The option about major roadwork reducing traffic volume provides an alternate cause for the drop in accidents.
An alternate cause severely weakens a causal conclusion by showing the stated effect could have occurred without the stated cause.

Key Concept

Evaluating Causal Arguments and Identifying Alternate Explanations
Question 20Question →

Argument: A recent study observed that individuals who consume green tea daily are significantly less likely to contract the common cold compared to those who do not drink green tea. The researchers concluded that specific antioxidants in green tea actively strengthen the immune system against cold viruses.

Statement: The new evidence that individuals who drink green tea daily are also much more likely to practice rigorous hand hygiene and avoid crowded places during cold season weakens the researchers' conclusion.

Show answer & explanation

Answer: True

Answer

True
The statement accurately reflects how to weaken a correlation-to-causation argument. By pointing out that the group experiencing fewer colds also engages in behaviors known to prevent illness (hand hygiene, avoiding crowds), the new evidence provides a strong alternate explanation for the outcome. This significantly weakens the researchers' conclusion that green tea was the determining factor.

Step-by-Step Solution

1
Analyze the original argument to identify the premise and conclusion.
The premise is a correlation between drinking green tea and having fewer colds. The conclusion is that green tea directly causes this reduction in colds.
Understanding the logical structure of the argument is essential for evaluating how new evidence affects it.
2
Examine the new evidence provided in the statement.
The evidence shows that green tea drinkers also share another trait: they practice better hygiene and avoid crowds.
We must understand the content of the new information to assess its logical impact.
3
Evaluate the impact of the new evidence on the argument's conclusion.
The new evidence provides an alternative cause (hygiene) for the effect (fewer colds), which makes the researchers' conclusion about green tea less likely to be the true cause.
Providing an alternate explanation for an observed correlation is a standard and effective method to weaken a causal conclusion.

Key Concept

Weakening a causal argument by providing an alternative explanation for an observed correlation.
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