Strengthen Questions in LSAT Logical Reasoning: Complete Mastery Guide
Strengthen questions represent approximately 10-15% of all LSAT Logical Reasoning questions, making them the second most common question type after flaw questions. Mastering strengthen questions is essential for achieving a competitive LSAT score, as they directly test your ability to evaluate how additional evidence impacts an argument—a fundamental skill for legal reasoning and case building. This comprehensive guide will equip you with proven strategies, systematic approaches, and expert techniques to confidently tackle strengthen questions and maximize your LSAT performance.
What Are Strengthen Questions?
A strengthen question asks you to identify which answer choice, if true, would make an argument's conclusion more likely to be correct or would provide additional support for the reasoning. Unlike sufficient assumptions (which must completely prove the conclusion), strengthen answers only need to improve the argument to some degree—they make it better, more convincing, or more probable.
The Law School Admission Council (LSAC) designs these questions to test your ability to determine how additional evidence affects an argument, which is crucial for legal reasoning, evaluating witness testimony, and assessing the impact of new evidence in legal cases.
Recognizing Strengthen Questions
Identifying strengthen questions immediately allows you to apply the appropriate strategy. Look for these key phrases in question stems:
- "Which one of the following, if true, most strengthens the argument?"
- "Which one of the following, if true, most strongly supports the conclusion?"
- "Which one of the following, if true, provides the most support for the hypothesis?"
- "Which one of the following, if true, most helps to justify the reasoning above?"
- "Which one of the following, if true, lends the most support to the claim?"
- "The argument would be most strengthened by which of the following?"
The key indicators are "strengthens," "supports," "most helps," "lends support," and variations of these phrases. Also notice the phrase "if true"—this tells you to accept the answer choice as fact and evaluate its impact on the argument.
Strengthen vs. Other Question Types
Understanding how strengthen questions differ from similar question types prevents confusion and helps you apply the correct approach.
| Aspect | Strengthen Question | Sufficient Assumption | Necessary Assumption |
|---|---|---|---|
| Goal | Make conclusion MORE LIKELY (any degree of improvement) | GUARANTEE conclusion is true (100% proof) | Identify what MUST be true for argument to work |
| Question Stem | "strengthens," "supports," "most helps" | "allows conclusion to be properly drawn," "justifies" | "assumes," "depends on," "requires" |
| Answer Strength | Variable—can be strong or moderate support | Very strong—must completely prove | Often minimal—just what's necessary |
| Test Method | Ask: "Does this make the conclusion more likely?" | Ask: "Does this prove the conclusion?" | Use negation test: "Does negating destroy argument?" |
| Impact on Argument | Improves but doesn't perfect | Makes completely valid | Reveals what argument relies on |
| Alternative Explanations | May eliminate some alternatives | Must eliminate all alternatives | Assumes no devastating alternatives exist |
Understanding Argument Structure
Before you can strengthen an argument, you must thoroughly understand its structure. Every LSAT argument consists of these components:
Argument Structure Formula:
Premises (Evidence) + Assumptions (Unstated Links) → Conclusion (Main Claim)
Identifying the Components
The Conclusion
What it is: The main point the author wants you to accept. It's what the argument is trying to prove.
How to find it: Look for conclusion indicators like "therefore," "thus," "consequently," "hence," "so," "it follows that," or "this shows that."
The test: Ask "What is the author's main point?" or "What is the author ultimately trying to convince me of?"
The Premises
What they are: The evidence, facts, or reasons given to support the conclusion.
How to find them: Look for premise indicators like "because," "since," "given that," "for," "as evidenced by," or "the reason is that."
The test: Ask "Why does the author think the conclusion is true? What evidence is provided?"
The Assumptions (Gaps)
What they are: Unstated links between premises and conclusion. These are logical leaps the author makes without explicitly stating them.
How to find them: Ask "What needs to be true to connect these premises to this conclusion?" or "What is the author taking for granted?"
Why they matter: Strengthen answers typically address these gaps by making the assumptions more likely to be true.
The Five-Step Strategy for Strengthen Questions
1Read the Question Stem First
Before reading the stimulus, look at the question stem to know you're dealing with a strengthen question. This primes your brain to think about gaps and vulnerabilities as you read the argument.
2Identify the Conclusion
Locate the main claim the argument is trying to prove. This is crucial because strengthen questions ask you to make THIS SPECIFIC CLAIM more believable or likely. Circle or mentally note the conclusion indicator and the conclusion itself.
Common conclusion locations:
- At the end (most common)
- At the beginning
- In the middle (less common but possible)
- Occasionally stated twice (rephrased for emphasis)
3Identify the Premises and Evidence
Map out all the supporting evidence. What facts, observations, or data does the author provide? Understanding the premises helps you see what support already exists and what's missing.
Example Breakdown:
Argument: "The new policy reduced traffic accidents by 15% in the first year. Therefore, the policy should be made permanent."
Conclusion: The policy should be made permanent.
Premise: The policy reduced traffic accidents by 15% in the first year.
4Identify the Gap (Missing Link)
This is THE MOST IMPORTANT STEP. Ask yourself: "Why doesn't the evidence automatically prove the conclusion? What's missing? What is the author assuming?" The gap is the vulnerability in the argument—the place where the logic could break down.
In our example above, potential gaps include:
- What if the reduction was temporary? (The conclusion assumes long-term effectiveness)
- What if there were negative side effects? (The conclusion assumes benefits outweigh costs)
- What if the reduction would have happened anyway? (The conclusion assumes the policy caused the reduction)
- What if 15% isn't significant enough? (The conclusion assumes this reduction justifies permanence)
5Predict What Would Strengthen the Argument
Before looking at answer choices, predict what kind of information would make the conclusion more believable. Your prediction should address one or more of the gaps you identified. Even if your prediction doesn't match the exact wording of the correct answer, this mental exercise keeps you focused on the argument's logic rather than getting distracted by attractive-sounding but irrelevant answer choices.
Predictions for our example:
- "The reduction has been sustained over three years" (addresses temporal concern)
- "No significant negative side effects occurred" (addresses cost-benefit concern)
- "Similar regions without the policy saw no accident reduction" (addresses causation)
- "A 15% reduction represents 500 lives saved annually" (addresses significance concern)
Three Main Ways to Strengthen an Argument
Understanding the different methods of strengthening helps you recognize correct answers and understand why they work.
Method 1: Strengthen the Conclusion Directly
How it works: Provide additional evidence that directly supports the conclusion itself, making it more likely to be true.
Example:
Conclusion: "Electric cars will dominate the market within 10 years."
Strengthen answer: "Major automakers have announced they will exclusively produce electric vehicles starting in five years."
Why it works: This adds new evidence that makes the predicted outcome more likely.
Method 2: Strengthen the Relevance of the Evidence
How it works: Show that the premises are actually relevant to and strongly connected to the conclusion. This addresses the gap between evidence and claim.
Example:
Premise: "Students who eat breakfast score higher on tests."
Conclusion: "Eating breakfast improves academic performance."
Strengthen answer: "The students studied came from diverse backgrounds with similar sleep schedules and study habits."
Why it works: This eliminates alternative explanations and shows the correlation is meaningful, not just coincidental.
Method 3: Eliminate Alternative Explanations
How it works: Rule out other possible explanations for the evidence, making the author's explanation (the conclusion) more likely to be correct.
Example:
Premise: "Sales increased after we launched the new advertising campaign."
Conclusion: "The advertising campaign caused the sales increase."
Strengthen answer: "No other factors changed during this period—prices, competition, and economic conditions remained constant."
Why it works: By eliminating alternative causes, this makes the claimed causal relationship more credible.
Common Argument Patterns and How to Strengthen Them
Pattern 1: Causal Arguments
Structure: X happened, then Y happened, therefore X caused Y.
Gap: Correlation doesn't prove causation. Maybe Y caused X (reverse causation), maybe Z caused both X and Y (common cause), or maybe it's pure coincidence.
How to strengthen:
- Eliminate alternative causes
- Show X consistently precedes Y
- Show the mechanism by which X causes Y
- Demonstrate X and Y are correlated across multiple contexts
- Rule out reverse causation
Example:
Argument: "After the city installed speed cameras, traffic accidents decreased. The speed cameras caused the decrease in accidents."
Strengthen answer: "No other traffic safety measures were implemented during this period, and weather conditions were typical."
Pattern 2: Predictive Arguments
Structure: Based on current evidence, X will happen in the future.
Gap: The future may differ from the present. Conditions might change, or the evidence might not be indicative of future trends.
How to strengthen:
- Show the current trend is accelerating or stable
- Eliminate factors that could disrupt the predicted outcome
- Provide evidence that similar predictions held true in the past
- Show that key factors influencing the outcome will remain constant
Example:
Argument: "Given the steady decline in newspaper subscriptions over the past decade, print newspapers will be obsolete within 20 years."
Strengthen answer: "The decline in subscriptions has actually accelerated each year, and no successful strategies to reverse this trend have been identified."
Pattern 3: Analogical Arguments
Structure: X and Y are similar. X has quality Z, therefore Y probably has quality Z too.
Gap: X and Y might not be similar in relevant ways, or they might have crucial differences that affect the comparison.
How to strengthen:
- Show X and Y are similar in ways RELEVANT to the quality being compared
- Eliminate significant differences between X and Y
- Show the similarity extends to the specific characteristic in question
Example:
Argument: "The tutoring program worked well at University A. It will likely work well at University B, which is similar in size and student demographics."
Strengthen answer: "Both universities have similar funding levels, administrative support structures, and student academic preparedness."
Pattern 4: Sampling/Generalization Arguments
Structure: Sample group shows characteristic X, therefore the larger population has characteristic X.
Gap: The sample might not be representative of the larger population.
How to strengthen:
- Show the sample is representative
- Show the sample is large enough
- Show the sample was randomly selected
- Eliminate sampling bias
Example:
Argument: "In a survey of 200 customers, 75% were satisfied with our product. Therefore, most of our customers are satisfied."
Strengthen answer: "The surveyed customers were randomly selected from all regions, age groups, and purchase dates, representing the full customer base."
Pattern 5: Arguments from Absence of Evidence
Structure: No evidence exists for X, therefore X is not true (or Y is true instead).
Gap: Absence of evidence isn't evidence of absence. Maybe we just haven't found the evidence yet.
How to strengthen:
- Show that evidence would have been found if it existed
- Show that thorough searches have been conducted
- Show that similar phenomena leave evidence under similar conditions
Example:
Argument: "No archaeological evidence of the ancient city has been found despite decades of searching. Therefore, the city probably never existed."
Strengthen answer: "Other cities from the same era and region have left extensive archaeological evidence that has been readily discovered."
Common Trap Answer Types
Recognizing trap answers saves time and increases accuracy. Here are the most common types:
Trap 1: The Out-of-Scope Answer
What it is: An answer that discusses topics, concepts, or issues not directly related to the argument's conclusion.
Why it's tempting: It might sound relevant to the general topic, but it doesn't address the specific gap between the premises and conclusion.
How to avoid it: Always ask, "Does this make THISSPECIFIC CONCLUSION more likely?" If the answer discusses something tangential, eliminate it.
Example:
Conclusion: "The new curriculum will improve student writing skills."
Trap answer: "Students are generally motivated to improve their grades."
Why it's wrong: Student motivation is relevant to education generally, but doesn't specifically address whether THIS curriculum improves writing.
Trap 2: The Premise Booster
What it is: An answer that supports or repeats a premise but doesn't bridge the gap to the conclusion.
Why it's tempting: It makes part of the argument stronger, so it feels like it strengthens something.
How to avoid it: Remember that premises are already accepted as true. The gap is between premises and conclusion, not within the premises themselves.
Example:
Premise: "Exercise reduces stress."
Conclusion: "People who exercise regularly are more productive at work."
Trap answer: "Multiple studies confirm that exercise significantly reduces stress levels."
Why it's wrong: This strengthens the premise, but the gap is "Does reduced stress lead to work productivity?" This answer doesn't address that link.
Trap 3: The Opposite (Weakener)
What it is: An answer that actually weakens the argument instead of strengthening it.
Why it's tempting: Carelessness, reading too quickly, or misunderstanding what the conclusion claims.
How to avoid it: Double-check that your selected answer makes the conclusion MORE likely, not less likely. Before finalizing your answer, quickly confirm the question asks for strengthen, not weaken.
Trap 4: The Comparison Shifter
What it is: An answer that addresses a different comparison than what the conclusion makes.
Why it's tempting: It involves similar concepts and sounds relevant.
How to avoid it: Pay close attention to exactly what is being compared in the conclusion. Make sure the answer addresses THAT SPECIFIC comparison.
Example:
Conclusion: "Product A is more cost-effective than Product B for small businesses."
Trap answer: "Product A is more popular than Product B among large corporations."
Why it's wrong: This compares popularity (not cost-effectiveness) and discusses large corporations (not small businesses). It's the wrong comparison on multiple dimensions.
Trap 5: The Shell Game (Subtle Term Shift)
What it is: An answer that uses similar-sounding terms but actually discusses something different from what the conclusion addresses.
Why it's tempting: The terms sound so similar that you might not notice the shift.
How to avoid it: Read carefully and watch for subtle distinctions between terms. "Most" vs. "many," "significant" vs. "some," "likely" vs. "possible," "cause" vs. "correlate."
Example:
Conclusion: "The policy will significantly reduce crime."
Trap answer: "The policy will have some effect on crime rates."
Why it's wrong: "Some effect" is much weaker than "significantly reduce." This doesn't actually strengthen the specific claim being made.
Advanced Techniques for Difficult Questions
Technique 1: The Impact Spectrum
When you're down to two answer choices, evaluate the magnitude of impact each would have on the argument. The correct answer usually has a more direct and substantial impact on the conclusion's likelihood.
Ask yourself:
- Which answer addresses the most significant gap?
- Which answer more directly connects to the conclusion?
- Which answer would make the biggest difference to someone evaluating this argument?
Technique 2: The Reversal Test
If you're unsure whether an answer strengthens or weakens (or does nothing), try reversing it. If reversing the answer would clearly weaken the argument, then the original answer strengthens it. If reversing it would strengthen the argument, the original answer weakens it. If reversing it makes no difference, it's likely out of scope.
Example:
Answer: "No other factors contributed to the observed effect."
Reversed: "Other factors contributed to the observed effect."
The reversed version clearly weakens a causal claim, so the original strengthens it.
Technique 3: The "So What?" Test
For each answer choice, ask "So what? How does this make the conclusion more likely?" If you can't articulate a clear connection, the answer probably doesn't strengthen effectively.
This test helps you avoid answers that sound impressive or relevant but don't actually impact the argument's logic.
Practice Strategy for Maximum Improvement
Strategic, deliberate practice is the key to mastering strengthen questions. Follow this systematic approach:
- Isolate Question Type: Do sets of 10-15 strengthen questions in one sitting. This focused practice helps you internalize patterns and recognition skills.
- Work Untimed Initially: For your first 50-100 strengthen questions, don't time yourself. Focus entirely on understanding the argument structure, identifying gaps correctly, and making accurate predictions.
- Predict Before Reading Answers: For EVERY question, write down your prediction before looking at answer choices. This builds your ability to engage with the argument's logic independently.
- Analyze Every Answer Choice: Don't just identify the right answer—understand why each wrong answer fails. Is it out of scope? Does it strengthen the premise instead of the gap? Does it address a different comparison? This analysis develops pattern recognition.
- Review Mistakes Systematically: Keep an error log. For each mistake, note: (1) The gap you should have identified, (2) Why you chose the wrong answer, (3) Why the right answer works, (4) What trap pattern you fell for. Over time, you'll notice your personal weak points.
- Compare with Weaken Questions: Occasionally alternate between strengthen and weaken questions to sharpen your ability to distinguish between them and to understand how the same argument can be attacked or supported.
- Progressive Timing: Once you hit 90%+ accuracy untimed, introduce timing gradually. Start at 2 minutes per question, then reduce to 1 minute 45 seconds, then to test conditions (approximately 1 minute 25 seconds).
- Use Official Materials Only: Practice exclusively with official LSAT PrepTests from LSAC. Third-party questions often miss the subtle logic patterns and trap answer structures of real LSAT questions.
Worked Example with Complete Analysis
Sample Question
Stimulus: "City planners have observed that neighborhoods with more trees have lower crime rates. Based on this observation, the city plans to plant thousands of trees in high-crime neighborhoods to reduce crime in those areas."
Question: "Which one of the following, if true, most strengthens the city planners' reasoning?"
Step-by-Step Solution
Step 1 - Question Stem Analysis: This is a strengthen question. We need to find what makes the planners' conclusion (planting trees will reduce crime) more believable.
Step 2 - Identify Conclusion: "Planting thousands of trees in high-crime neighborhoods will reduce crime in those areas."
Step 3 - Identify Premises: "Neighborhoods with more trees have lower crime rates."
Step 4 - Identify the Gap: This is a classic correlation-to-causation argument. The planners observe a correlation (more trees = less crime) and conclude causation (trees reduce crime). But what if:
- Wealthy neighborhoods have both more trees AND less crime, and wealth is the real factor?
- Low-crime neighborhoods choose to plant trees, not the other way around?
- Some other factor causes both more trees and less crime?
- The correlation is coincidental?
Step 5 - Predict Strengthener: Something that eliminates alternative explanations or shows trees actually cause crime reduction. Examples:
- "When trees were planted in previously treeless neighborhoods, crime rates subsequently declined"
- "Neighborhoods with similar demographics and economic conditions differ only in tree coverage, with tree-covered areas having less crime"
- "The presence of trees has been shown to increase community interaction and natural surveillance, factors that deter crime"
Evaluating Answer Choices
(A) "The neighborhoods with the most trees are among the wealthiest in the city."
Analysis: This WEAKENS the argument by suggesting an alternative explanation (wealth, not trees, causes low crime). Eliminate. ✗
(B) "Trees require regular maintenance to remain healthy and attractive."
Analysis: This is about tree maintenance, not about the relationship between trees and crime. Out of scope. Eliminate. ✗
(C) "Crime rates in neighborhoods are affected by many factors including employment, education, and community programs."
Analysis: While true, this doesn't help the planners' specific argument. If anything, it suggests crime is complex and tree-planting might not be effective. Doesn't strengthen. Eliminate. ✗
(D) "Experimental tree-planting programs in similar cities led to measurable crime reductions in the targeted neighborhoods."
Analysis: This is strong! It shows that tree-planting has actually CAUSED crime reduction in similar contexts, not just correlated with it. This addresses the causation gap. Keep. ✓
(E) "Residents of neighborhoods with many trees report feeling safer than residents of neighborhoods with few trees."
Analysis: Feeling safer is related but doesn't prove actual crime reduction. People might feel safer but crime rates could be the same. Doesn't directly strengthen the conclusion about actual crime reduction. Eliminate. ✗
Correct Answer: (D)
Why it works: Answer (D) provides experimental evidence that planting trees CAUSES crime reduction, not just correlates with it. By showing this has worked in "similar cities," it makes the planners' prediction for their city more credible. This directly strengthens the causal reasoning in the argument.
Frequently Asked Questions
Official LSAT Resources
Maximize your LSAT preparation with these official resources from the Law School Admission Council (LSAC):
LSAC Official Logical Reasoning Overview LSAC Official Sample Questions LSAC LawHub Prep Platform Official LSAT PrepTests LSAT Test Dates and RegistrationMastering Strengthen Questions: Your Path to LSAT Success
Strengthen questions test a fundamental legal skill: evaluating how additional evidence impacts an argument. This ability is essential for building cases, evaluating witness testimony, assessing expert opinions, and determining what additional evidence would support a legal claim. By mastering the systematic approach outlined in this guide—identifying conclusions and premises accurately, spotting gaps precisely, predicting strengtheners strategically, and recognizing trap answers quickly—you'll develop the analytical skills that will serve you throughout your LSAT, in law school, and in your legal career. Practice consistently with official LSAT PrepTests, analyze your errors thoroughly, and focus on understanding WHY correct answers strengthen and wrong answers don't. With dedicated practice and the strategies you've learned here, you'll gain the confidence and precision needed to excel on strengthen questions and achieve your target LSAT score.
