Practice Strengthen & Weaken Arguments questions for the Law School Admission Test. Every question includes a full explanation of why the correct answer is right and why the tempting distractors are wrong.
16 questions available · medium difficulty · LSAT · Free, no registration required
10 example questions with full explanations. Use the interactive practice above to work through the complete set.
Question 1medium
A city council member argues: 'Our new late-night public transit program has reduced drunk driving incidents. Since the program launched six months ago, DUI arrests in the city have dropped by 18%.' Select all that apply: Which of the following, if true, would WEAKEN the council member's argument?
- A.A new sobriety checkpoint initiative by the police department launched in the same month as the transit program, leading officers to issue warnings rather than arrests for first-time offenders.✓
- B.Ridership on the late-night transit program has steadily increased each month since its launch.
- C.A survey found that 60% of late-night transit riders report they previously would have driven after drinking.
- D.The 18% drop in DUI arrests mirrors a statewide trend in cities that did not implement any new transit programs during the same period.✓
Correct answer: A, D
The argument concludes that the transit program caused the drop in DUI arrests. Answer A weakens it by introducing an alternative cause: a simultaneous checkpoint policy that changed how arrests were counted, meaning fewer arrests may not reflect fewer drunk drivers. Answer D weakens it by showing the same trend occurred elsewhere without the program, undermining the causal link. Answer B actually strengthens the argument by showing the program is being used. Answer C also strengthens the argument by suggesting riders were previously drunk drivers, supporting a causal connection.
Question 2medium
A nutrition researcher concludes: 'Eating breakfast every day improves academic performance in school-aged children. In our study, children who ate breakfast daily scored, on average, 12% higher on standardized tests than children who skipped breakfast regularly.' Select all that apply: Which of the following, if true, would STRENGTHEN the researcher's argument?
- A.The children in the study who ate breakfast daily came from households with higher incomes on average than those who skipped breakfast.
- B.When children who previously skipped breakfast were provided free school breakfasts and began eating daily, their test scores rose by an average of 11% within one semester.✓
- C.A controlled laboratory study found that glucose levels in the brain are measurably higher in the hours following breakfast consumption, and higher glucose levels are associated with improved cognitive function.✓
- D.The standardized tests used in the study have been criticized by some educators for measuring rote memorization rather than critical thinking.
Correct answer: B, C
The argument claims breakfast causes improved academic performance. Answer B strengthens it by ruling out an alternative explanation (perhaps high-performing students just happen to eat breakfast) — the before-and-after design shows test scores actually improved when breakfast was added, confirming causation. Answer C strengthens it by providing a plausible biological mechanism that supports the causal claim. Answer A weakens the argument by suggesting income (a confounding variable) may explain both breakfast-eating habits and test performance. Answer D is irrelevant to whether breakfast improves whatever the tests actually measure.
Question 3medium
An economist argues: 'Raising the minimum wage in Maplewood County will not lead to increased unemployment among low-wage workers. Historical data from other counties show that minimum wage increases have rarely caused significant job losses.' Select all that apply: Which of the following, if true, would WEAKEN this argument?
- A.The counties cited in the historical data are major urban centers with diverse, service-dominated economies, while Maplewood County is a small, manufacturing-dependent rural community where labor costs constitute a much higher share of production costs.✓
- B.Several economists who have studied minimum wage policy agree that moderate increases have limited employment effects in most markets.
- C.Two of the three largest employers in Maplewood County have publicly stated they will automate entry-level positions if the minimum wage rises above a specific threshold that the proposed increase would exceed.✓
- D.The proposed minimum wage increase in Maplewood County is smaller in absolute dollar terms than most of the increases recorded in the historical data cited by the economist.
Correct answer: A, C
The economist uses historical data from other counties to predict Maplewood's outcome. Answer A weakens by showing the sample is unrepresentative — the cited counties are fundamentally different from Maplewood in ways that affect how wage increases impact employment. Answer C weakens by providing a counter-example and a specific mechanism for job loss in Maplewood, directly undermining the conclusion. Answer B strengthens the argument by providing expert support. Answer D actually strengthens the argument, since a smaller increase is even less likely to cause disruption than the increases that historically had little effect.
Question 4medium
A criminologist states: 'Stricter sentencing laws do not deter violent crime. Studies in the 1990s found no significant correlation between sentence length and violent crime rates across different states.' Select all that apply: Which of the following, if true, most directly WEAKEN the criminologist's argument?
- A.A more recent meta-analysis of sentencing studies found that the 1990s research systematically failed to distinguish between crimes committed by first-time offenders and repeat offenders, two groups that respond very differently to sentencing policy.✓
- B.Several states with the strictest sentencing laws in the 1990s also had the highest rates of poverty and unemployment, factors independently associated with higher violent crime rates.✓
- C.Criminologists generally agree that it is difficult to study the deterrent effects of sentencing laws because of the large number of variables involved.
- D.Researchers have found that the certainty of being caught, not the severity of punishment, is the primary factor that potential offenders consider; however, this relationship holds only when sentence lengths fall below a minimum threshold that most states in the 1990s had not yet reached.✓
Correct answer: A, B, D
The argument relies on 1990s correlation studies to conclude sentencing does not deter crime. Answer A weakens it by attacking a premise — if the studies were methodologically flawed (conflating offender types), their null finding is unreliable. Answer B weakens it by introducing a confounding variable: high-sentence states also had high poverty, which could mask a genuine deterrent effect of sentencing, making the lack of correlation uninformative. Answer D weakens it by suggesting the studies' conditions (pre-threshold sentence lengths) mean they never actually tested effective deterrence, so the null result is inapplicable. Answer C is a general observation about research difficulty that, if anything, casts doubt on all sentencing research equally and does not specifically weaken this conclusion.
Question 5hard
A pharmaceutical company argues that its new antidepressant is effective because in clinical trials, 70% of patients who completed the full 12-week course reported significant improvement in symptoms. A researcher challenges this conclusion by pointing out that only 40% of enrolled patients actually completed the full course, while the rest dropped out early — many citing worsening symptoms or intolerable side effects. Which of the following, if true, most strongly weakens the researcher's challenge to the company's argument?
The company's conclusion: The antidepressant is effective.
The researcher's challenge: The 70% improvement rate is misleading because it excludes patients who fared poorly.
- A.Independent follow-up studies of patients who dropped out of the trial found that the majority had switched to older antidepressants, which are known to produce high dropout rates even among patients who ultimately recover.
- B.The rate of dropout in the company's trial was not statistically different from dropout rates in trials of other antidepressants that are already approved and widely prescribed.
- C.Regulatory agencies require pharmaceutical companies to report both completion rates and symptom improvement rates when submitting drug approval applications.
- D.Among the patients who dropped out, exit interviews revealed that over half reported their primary reason for leaving was logistical — scheduling conflicts and transportation difficulties — rather than worsening symptoms or side effects.✓
Correct answer: D
The researcher's challenge is a survivorship-bias argument: the 70% success rate is derived from a cherry-picked sample (completers), while those who fared worst (dropouts) are excluded. The researcher assumes the dropouts left because of poor outcomes, which would make the completer sample unrepresentative. Answer C directly dismantles this assumption by showing that the majority of dropouts left for logistical reasons, not due to worsening symptoms or side effects — meaning their exclusion does not systematically bias the sample toward better outcomes. This defeats the researcher's core claim. Answer A is tempting but concerns what dropouts did afterward, not why they dropped out, so it does not address the bias concern. Answer B normalizes the dropout rate comparatively but does not address whether the remaining sample is biased. Answer C is irrelevant to the validity of the researcher's statistical challenge.
Question 6hard
An urban planner argues: 'Our city should adopt a congestion pricing scheme — charging drivers a fee to enter the downtown core during peak hours. London implemented this policy in 2003, and within a year, downtown traffic decreased by 30% and public transit ridership increased by 15%. Therefore, our city can expect similar benefits if we implement the same policy.' Which of the following most strongly strengthens this argument?
- A.The city has a public transit network of comparable coverage and capacity to London's at the time of its congestion pricing implementation, and its downtown workforce commutes from distances similar to London commuters.✓
- B.Surveys show that a majority of the city's residents support reducing downtown traffic congestion and are aware that congestion pricing has been used successfully in other cities.
- C.Several economists who specialize in transportation policy have publicly endorsed congestion pricing as a theoretically sound mechanism for reducing traffic externalities.
- D.The revenue generated by London's congestion charge was reinvested into the city's bus network, contributing to the ridership increase observed after implementation.
Correct answer: A
The argument is an analogical argument — it concludes that what worked in London will work in this city. The critical gap is whether this city is sufficiently similar to London in the relevant respects to warrant the same prediction. Answer A directly addresses this gap by confirming that the two cities share the key structural features (transit coverage, capacity, and commuter geography) that would make the policy function similarly — it confirms the analogy's necessary assumption. Answer A shows public support, which relates to political feasibility but not to whether the policy will produce the predicted traffic and transit effects. Answer C provides expert endorsement of the general theory but does not show the cities are comparable. Answer D actually explains London's mechanism but, if anything, raises a question about whether this city will also reinvest revenue similarly — it does not straightforwardly strengthen the conclusion that similar benefits will follow.
Question 7hard
A legal advocacy group publishes the following argument: 'Mandatory minimum sentencing laws are unjust. Under these laws, judges are required to impose fixed prison terms regardless of mitigating circumstances. Justice requires that punishment be proportionate to the individual's culpability. Since mandatory minimums strip judges of the discretion needed to achieve proportionate sentencing, they violate the principle of justice.' A legislator responds: 'Mandatory minimums are justified because they deter crime more effectively than discretionary sentencing.' Which of the following principles, if established, would most strongly support the advocacy group's argument against the legislator's response?
- A.Policies that produce socially beneficial outcomes are justified even if they conflict with abstract principles of individual fairness.
- B.A sentencing policy cannot be considered just if it regularly produces outcomes that violate the principle of proportionality, regardless of any deterrent effect it may have.✓
- C.The primary purpose of criminal sentencing should be the rehabilitation of offenders rather than the deterrence of future crimes.
- D.Judges should be given full discretion in sentencing decisions in order to ensure that the unique circumstances of each case are properly weighed.
Correct answer: B
This is a principle-strengthening question. The advocacy group's argument concludes that mandatory minimums are unjust because they violate proportionality. The legislator's rebuttal pivots to deterrence — a consequentialist justification that sidesteps the justice/proportionality framework. The advocacy group needs a principle that blocks this pivot by establishing that deterrent effectiveness cannot override proportionality concerns. Answer B does exactly this: it states that no amount of deterrent effect can redeem a policy that systematically violates proportionality — directly defeating the legislator's move. Answer A supports the legislator's position, not the advocacy group's. Answer C challenges deterrence theory on rehabilitative grounds but does not address the proportionality principle central to the advocacy group's argument. Answer D argues for judicial discretion as a practical remedy but does not provide the normative principle needed to rebut the legislator's consequentialist defense.
Question 8hard
A nutritionist claims: 'Consumers who switch from white bread to whole-grain bread will reduce their risk of developing type 2 diabetes. Studies consistently show that people who eat whole grains have significantly lower rates of type 2 diabetes than people who eat refined grains.' A critic responds that the studies are observational, and people who eat whole grains also tend to exercise more, smoke less, and have higher incomes — making it impossible to attribute the lower diabetes rates to bread type alone. The nutritionist replies: 'But several of those studies statistically controlled for exercise, smoking, and income, and the association between whole grain consumption and lower diabetes risk remained significant.' Evaluate the degree to which the nutritionist's reply strengthens her original conclusion.
- A.The reply fully restores the original conclusion because statistical controls eliminate confounding variables, making the study equivalent in validity to a randomized controlled trial.
- B.The reply does not strengthen the original conclusion at all because observational studies, regardless of statistical controls applied, can never establish causal relationships.
- C.The reply substantially strengthens the original conclusion by ruling out three major confounds, though it cannot exclude the possibility that other unmeasured lifestyle factors account for the association.✓
- D.The reply weakens the original conclusion because it concedes that the studies were observational, which the nutritionist had not previously acknowledged.
Correct answer: C
This question tests the nuanced concept of degree of strengthening in the context of confound control. The critic identifies alternative explanations (confounds). The nutritionist's reply rules out three specific confounds via statistical control, which genuinely strengthens her argument — but statistical control in observational studies cannot account for unmeasured variables, and it does not establish causation as rigorously as a randomized controlled trial. Answer B correctly captures this: the reply substantially (but not fully) strengthens the argument by eliminating the named confounds while acknowledging residual uncertainty. Answer A overstates the strength — statistical controls do not make observational studies equivalent to RCTs; residual confounding from unmeasured variables remains. Answer B is too absolute — the claim that observational studies 'can never' establish causal relationships ignores that controlling for confounds meaningfully increases evidentiary weight. Answer D misreads the argumentative situation; acknowledging the study design is observational does not undercut the conclusion — it was always implicit, and the controls partially address the concern.
Question 9hard
A city council member argues: 'Our proposal to install surveillance cameras throughout the downtown area will reduce street crime. Last year, Riverside City installed cameras in its downtown, and street crime there dropped by 22% in the following six months. The cameras clearly deterred criminals.' A colleague replies: 'Actually, Riverside City also launched a downtown community policing initiative at the same time as the cameras were installed.' Which of the following, if true, most strongly undermines the colleague's attempt to weaken the council member's argument?
- A.Community policing initiatives in other cities have produced average crime reductions of only 5–8%, well below the 22% reduction seen in Riverside City.
- B.Criminologists who studied Riverside City's crime data concluded that both the cameras and the policing initiative likely contributed to the decline, with neither factor sufficient alone.
- C.Several downtown business owners in Riverside City reported feeling safer after the cameras were installed, suggesting the cameras had a visible deterrent effect.
- D.The community policing initiative in Riverside City was limited to residential neighborhoods and was not deployed in the downtown area where the cameras were installed and the crime reduction was measured.✓
Correct answer: D
The colleague's move is a classic alternative-cause weakener: the crime drop may have been caused by the community policing initiative rather than (or in addition to) the cameras. To undermine this weakener, the council member needs to show that the alternative cause (community policing) either did not exist in the relevant area or could not plausibly explain the outcome. Answer C does exactly this: it establishes that the community policing initiative was geographically confined to residential neighborhoods and was absent from the downtown area where both the cameras and the crime reduction were located — effectively severing the causal link the colleague implied. Answer A shows that policing initiatives typically produce smaller reductions, which suggests cameras contributed more, but it does not rule out policing as a partial cause. Answer B actually concedes that both factors contributed, which partially validates the colleague's point rather than defeating it. Answer C provides anecdotal business owner perceptions, which suggest a deterrent effect but do not address whether the policing initiative was a confounding cause.
Question 10easy
A nutritionist argues: 'Residents of Valmont County who eat breakfast every day have lower rates of obesity than those who skip breakfast. Therefore, eating breakfast daily causes lower obesity rates.' Which of the following, if true, most weakens the nutritionist's argument?
- A.Residents who eat breakfast daily also tend to exercise more regularly than those who skip breakfast.✓
- B.Some residents of Valmont County who eat breakfast daily are still obese.
- C.The nutritionist conducted the study over a period of five years.
- D.Breakfast foods in Valmont County tend to be high in protein.
Correct answer: A
The nutritionist concludes that eating breakfast causes lower obesity rates based on a correlation. Answer A introduces an alternative cause — regular exercise — that could explain the lower obesity rates among breakfast eaters, undermining the causal conclusion. Answer A merely shows the relationship isn't absolute, which doesn't directly attack the causal claim. Answer C strengthens the study's credibility. Answer D is irrelevant to whether breakfast itself causes the effect.