Flaw Questions
Key Takeaways
- Flaw answers describe the reasoning error already present; they usually do not add new evidence.
- The correct answer must match the argument's specific support-to-conclusion failure, not merely name a common fallacy.
- Causal, sampling, comparison, conditional, analogy, and equivocation flaws recur, but the exact wording must fit the stimulus.
- A flaw answer can be abstract, but it still has to preserve the argument's scope and conclusion strength.
Flaw Means Diagnosis
A flaw question asks what is wrong with the reasoning. The answer is usually not a new fact and not a better argument. It is a diagnosis of the mistake the author has already made. That is why a flaw stem feels close to weaken but is not the same task.
LSAC's public guidance tells test takers not to select a response simply because it is true. Flaw questions are a perfect example. A statement can be a real criticism in life but still fail if it does not describe this author's actual logical move.
Flaw Versus Weaken
| Task | Correct answer usually | Example function |
|---|---|---|
| Flaw | describes the defect | says the author infers cause from timing |
| Weaken | adds damaging information | says another event occurred at the same time |
| Method | neutrally describes structure | says the author applies a rule to a case |
| Role | describes one statement's job | says a sentence is a premise |
The distinction is practical. If an answer begins by saying the argument overlooks, presumes, infers, fails to consider, or takes for granted, it may be a flaw description. If it gives a new fact about the world, it may be a weakener, not a flaw answer.
Name The Error Before Choices
Start with the argument core. What evidence is offered? What conclusion is drawn? What leap occurs? Then state the flaw in your own words. Good prephrases are specific: before-after cause, unrepresentative survey, necessary condition treated as sufficient, percent-to-number shift, analogy ignores relevant difference.
Avoid generic labels if they hide the issue. Saying the argument is invalid is too broad. Saying it assumes a plan will work because a related plan worked elsewhere is useful. Saying it fails to rule out alternate causes is useful only if the stimulus actually makes a causal claim.
High-Frequency Flaw Families
| Family | Author's move | Diagnostic question |
|---|---|---|
| Causal | correlation or sequence -> cause | What else could explain the effect? |
| Sampling | limited group -> broad claim | Who was included and who was excluded? |
| Conditional | required condition -> enough condition | Which direction does the rule run? |
| Comparison | one measure -> overall superiority | Are the compared bases the same? |
| Analogy | case A -> case B | Is the shared feature relevant? |
| Equivocation | same word -> shifted meaning | Did the key term change? |
| Authority | source says X -> X true | Is the expertise relevant and reliable? |
These families are tools, not answer keys. The correct answer must fit the stimulus. A causal flaw answer is wrong on a conditional argument, even if causal flaws are common.
Match Scope And Force
Flaw answer choices often overstate. If the author says a policy is likely to reduce delays, a choice saying the author assumes it will eliminate all delays may be too strong. If the author uses one small survey to support a citywide claim, a choice saying the survey was not representative may fit better than a choice saying no survey evidence can ever support public policy.
Force words matter: all, never, only, prove, guarantee, and must can distort the criticism. But do not eliminate strong wording automatically. If the author truly makes a universal conclusion from weak support, a strong criticism may be exactly right.
Flaw choices can also be underinclusive. If an answer describes only one minor consequence while the real problem is a category shift, it misses the target. Use the conclusion as the boundary for the criticism.
Causal Flaw Precision
Not every causal flaw is the same. A before-after argument may ignore other changes during the same period. A correlation argument may ignore a third factor or reverse causation. A comparison between groups may ignore selection bias. The answer should identify the relevant causal weakness.
For example, if applicants who used a prep course scored higher and the author concludes the course caused the scores, the best flaw may be self-selection: stronger or more motivated applicants may have chosen the course. A generic answer about not proving causation may be acceptable only if it is the most precise available.
Formal Flaws
Conditional flaws are easier when translated. If the passage says every licensed mediator has completed training, then completed training is necessary for licensed mediators. An argument that someone completed training, therefore is licensed, treats a necessary condition as sufficient. A flaw answer should preserve that direction.
Parallel-flaw questions can later ask you to match the same error, so review formal flaws in abstract form. Write if licensed -> trained; trained; therefore licensed. Then label it as affirming the necessary condition.
Review That Builds Skill
After each flaw miss, record two lines: the author's leap and the credited criticism. Do not write only the fallacy name. Write the operational pattern: infers effectiveness from users who self-selected, generalizes from downtown shoppers to all residents, or treats a required permit as enough for approval.
Use three review labels:
- Error family.
- Exact conclusion affected.
- Why the tempting answer missed the task.
Also review tempting wrong answers. Ask whether they were wrong task, wrong scope, wrong flaw family, or too extreme. That classification prevents the same trap from returning.
The best flaw work is disciplined and local. You are not asked to give the author's argument a grade in real life. You are asked to identify the specific reason the stated evidence does not justify the stated conclusion.
Arts director: After the community arts center began offering late-night gallery hours, annual membership renewals increased for the first time in five years. Clearly, the late-night hours caused renewed interest in membership. The director's reasoning is most vulnerable to which criticism?