**GRE Reading Comprehension: Critical Reasoning – Argument Structure, Assumption, & Flaw Questions**

GRE Reading Comprehension: Critical Reasoning – Argument Structure, Assumption, & Flaw Questions

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What This Is

Critical Reasoning questions test your ability to analyze, evaluate, and strengthen or weaken arguments—a skill the GRE uses to predict your success in graduate-level reasoning. These questions appear in Reading Comprehension (RC) passages (usually 1–2 per passage) and are among the most time-consuming and high-value Verbal questions. Mastering them can boost your Verbal score by 3–5 points by helping you avoid traps, spot assumptions, and quickly eliminate wrong answers.

Example GRE-Style Question:

Editorial: The city’s new policy of fining residents who fail to recycle will reduce landfill waste. After all, a similar policy in neighboring Greenvale led to a 20% decrease in landfill waste within six months. Which of the following is an assumption required by the editorial’s argument? (A) Greenvale’s recycling infrastructure is identical to that of the city.
(B) Residents in Greenvale were not already recycling before the policy was implemented.
(C) The city’s residents are as responsive to financial penalties as Greenvale’s residents.
(D) The 20% decrease in Greenvale’s landfill waste was solely due to the recycling policy.
(E) The city’s landfill waste will decrease by at least 20% under the new policy.

(Answer: C. The argument assumes the two cities’ residents respond similarly to fines.)

Key Concepts & Techniques

1. Identify the Core Argument (Conclusion + Premises)
2. What it is: Every argument has a conclusion (the claim being made) and premises (evidence supporting it).
3. When to use it: First step in every Critical Reasoning question. Locate the conclusion (look for signal words like thus, therefore, clearly, shows that) and underline the premises.

4. Example: In the question above, the conclusion is “The city’s new policy will reduce landfill waste,” and the premise is “Greenvale’s similar policy reduced waste by 20%.”

5. Spot the Logical Gap (Assumption Questions)

6. What it is: An assumption is an unstated premise that must be true for the argument to hold. It bridges the gap between premises and conclusion.
7. When to use it: For Assumption questions (e.g., “Which of the following is an assumption required by the argument?”).

8. How to find it: Ask: “What must be true for the conclusion to follow from the premises?” Use the Negation Test (see Step-by-Step Strategy).

9. Predict the Assumption/Flaw Before Looking at Answers

10. What it is: Before reading answer choices, articulate the missing link or flaw in your own words.
11. When to use it: Always. This prevents you from being swayed by trap answers.

12. Example: In the sample question, the gap is: “Does Greenvale’s success guarantee the city’s success?” The assumption must address this.

13. Weaken/Strengthen Questions: Attack the Gap

14. What it is: To weaken an argument, find an answer that exposes the assumption (e.g., “What if the two cities are different in a key way?”). To strengthen, support the assumption (e.g., “What if the two cities are identical in the relevant way?”).

15. When to use it: For Weaken/Strengthen questions (e.g., “Which of the following, if true, most weakens the argument?”).

16. Flaw Questions: Name the Error

17. What it is: A flaw is a logical error in the argument (e.g., correlation ≠ causation, hasty generalization, false analogy).
18. When to use it: For Flaw questions (e.g., “The argument is most vulnerable to which of the following criticisms?”).

19. Common Flaws:

    
    
    • False analogy: Comparing two things that aren’t truly comparable.
    • Circular reasoning: The conclusion restates the premise.
    • Overlooked alternatives: Ignoring other possible explanations.
    • Causation vs. correlation: Assuming X causes Y just because they’re related.

20. The Negation Test (For Assumption Questions)

21. What it is: If you negate the correct assumption, the argument falls apart. If negating an answer choice doesn’t destroy the argument, it’s not the assumption.
22. When to use it: When stuck between 2–3 answer choices in an Assumption question.

23. Example: Negate (C) from the sample question: “The city’s residents are not as responsive to financial penalties as Greenvale’s residents.” This destroys the argument, confirming (C) is the assumption.

24. Eliminate Trap Answers

25. What it is: The GRE loves plausible but irrelevant answer choices. Learn to spot them.
26. When to use it: Every question. Common traps:
    • Out of scope: Introduces new information not in the argument.
    • Too extreme: Uses words like always, never, all, none.
    • Reverse logic: Strengthens when you need to weaken (or vice versa).
    • Half-right: Partially addresses the argument but misses the key gap.

Step-by-Step Strategy

Follow these steps for every Critical Reasoning question:

1. Read the Question First
2. Identify the question type (Assumption, Flaw, Weaken, Strengthen, etc.).

3. Underline key words (e.g., “assumption,” “weakens,” “vulnerable to criticism”).

4. Break Down the Argument

5. Find the conclusion (the main claim).
6. Find the premises (the evidence).

7. Articulate the gap in your own words (e.g., “The argument assumes X, but what if Y?”).

8. Predict the Answer

9. For Assumption/Flaw questions, state the missing link or error before looking at answers.

10. For Weaken/Strengthen, think: “What would make the argument stronger/weaker?”

11. Evaluate Answer Choices

12. Eliminate traps (out of scope, extreme, reverse logic).
13. Use the Negation Test for Assumption questions if stuck.

14. Compare remaining choices to your prediction.

15. Confirm the Best Answer

16. The correct answer must directly address the gap or flaw.
17. If two choices seem close, re-read the argument—one will be more precise.

Fully Worked GRE-Style Example

Question:

Politician: Our nation’s healthcare system is inefficient because it is a government-run system. In contrast, countries with privately run healthcare systems, such as Switzerland, have shorter wait times for medical procedures. Therefore, we should privatize our healthcare system to reduce wait times. The politician’s argument is most vulnerable to which of the following criticisms?

Step 1: Read the Question First
- Question type: Flaw (“most vulnerable to which criticism”).

Step 2: Break Down the Argument
- Conclusion: We should privatize healthcare to reduce wait times.
- Premises:
1. Government-run healthcare is inefficient.
2. Switzerland (private healthcare) has shorter wait times.
- Gap: The argument assumes that privatization is the only reason for Switzerland’s shorter wait times (ignoring other factors like funding, population size, or healthcare infrastructure).

Step 3: Predict the Answer
- The flaw is overlooking alternative explanations for Switzerland’s shorter wait times. The argument assumes causation (privatization → shorter wait times) without ruling out other causes.

Step 4: Evaluate Answer Choices
- (A) It assumes that what is true of Switzerland’s healthcare system is true of all privately run systems. - Trap: This is a hasty generalization, but the argument doesn’t claim all private systems are better—just that Switzerland’s is.
- (B) It overlooks the possibility that factors other than privatization contribute to Switzerland’s shorter wait times. - Correct: This matches our prediction—overlooked alternatives.
- (C) It fails to consider that government-run healthcare systems might have advantages not mentioned. - Trap: Irrelevant. The argument is about wait times, not other advantages.
- (D) It assumes that reducing wait times is the only goal of healthcare reform. - Trap: The argument doesn’t claim this—it’s about efficiency, not only wait times.
- (E) It ignores the possibility that Switzerland’s healthcare system is not truly privatized. - Trap: The argument doesn’t need to prove Switzerland’s system is fully private—just that it’s more private than the nation’s.

Step 5: Confirm the Best Answer
- (B) directly addresses the flaw: the argument ignores other possible causes for Switzerland’s shorter wait times.

Common Mistakes

GRE Traps & Timing

Traps to Watch For

1. False Analogy Trap
2. The argument compares two things (e.g., two cities, two policies) and assumes they’re identical in all relevant ways.
3. How to spot it: Look for comparisons (“like X, Y will…”). Ask: “Are these really comparable?”

4. Example: The sample question compares Greenvale and the city—are their residents equally responsive to fines?

5. Causation vs. Correlation Trap

6. The argument assumes X causes Y just because they’re related.
7. How to spot it: Look for phrases like “led to,” “resulted in,” “caused by.”

8. Example: “Ice cream sales increase in summer, and drowning deaths increase in summer. Therefore, ice cream causes drowning.” (Ignores a third factor: heat.)

9. Overlooked Alternatives Trap

10. The argument ignores other possible explanations for the evidence.
11. How to spot it: Ask: “Could something else explain this?”

12. Example: “The new CEO took over, and profits rose. Therefore, the CEO caused the profit increase.” (Ignores market trends, cost-cutting, etc.)

13. Reverse Logic Trap

14. The answer choice does the opposite of what the question asks (e.g., strengthens when you need to weaken).
15. How to spot it: Double-check the question type before selecting an answer.

Timing

• Assumption/Flaw questions: 90–105 seconds (spend extra time predicting the gap).
• Weaken/Strengthen questions: 75–90 seconds (focus on attacking the assumption).
• If stuck: Flag and move on—don’t spend >2 minutes on one question.

Quick Practice

Question 1 (Assumption):

A study found that employees who work from home are 15% more productive than those who work in the office. Therefore, the company should allow all employees to work from home to increase overall productivity. Which of the following is an assumption required by the argument? (A) The productivity increase is due to working from home rather than other factors.
(B) Employees who work from home are happier than those who work in the office.
(C) The company’s office environment is not conducive to productivity.
(D) All employees are equally capable of working productively from home.
(E) The study’s sample size was large enough to be representative.

Answer: (D) Explanation: The argument assumes that all employees can be productive at home—if some can’t, the conclusion fails. (A) is a trap—it’s a strengthener, not an assumption.

Question 2 (Flaw):

Critic: The new action movie received poor reviews from film critics. Therefore, audiences will not enjoy it. The critic’s argument is most vulnerable to which of the following criticisms? (A) It assumes that critics and audiences have the same taste in movies.
(B) It overlooks the possibility that the movie was poorly marketed.
(C) It ignores the fact that some critics may have personal biases.
(D) It fails to consider that audiences may enjoy movies that critics dislike.
(E) It assumes that all action movies are equally likely to receive poor reviews.

Answer: (A) Explanation: The flaw is assuming critics’ opinions = audiences’ opinions. (D) is close but too narrow—the argument doesn’t just “fail to consider” this; it assumes the opposite.

Last-Minute Cram Sheet

1. Assumption = Unstated premise that must be true for the argument to hold.
2. Flaw = Logical error (e.g., false analogy, causation ≠ correlation, overlooked alternatives).
3. Weaken = Attack the assumption (expose the gap).
4. Strengthen = Support the assumption (fill the gap).
5. Negation Test: If negating the answer destroys the argument, it’s the assumption.
6. Trap: Out of scope = Irrelevant to the argument’s gap.
7. Trap: Extreme language = “All,” “never,” “only” (usually wrong).
8. Trap: Reverse logic = Does the opposite of what the question asks.
9. Always predict first—don’t look at answers until you’ve articulated the gap/flaw.
10. Time budget: 90 sec for Assumption/Flaw, 75 sec for Weaken/Strengthen.

Final Tip: On test day, underline the conclusion and circle the gap in every Critical Reasoning question. This forces you to engage with the argument’s logic, not just its words.