Quick answer: a Flaw question asks you to describe the mistake in an argument. Everything you need is already on the page. Say the mistake in your own words first, then match it to an answer, which is often written in abstract language.
How to Spot Flaw Questions
Look for question stems like these:
- The reasoning in the argument is flawed because the argument…
- Which one of the following most accurately describes a flaw in the reasoning?
- The argument is most vulnerable to criticism on the grounds that it…
How to Solve Flaw Questions
- Find the conclusion and the evidence.
- Ask why the evidence does not fully prove the conclusion.
- Name the flaw in plain words.
- Read each answer slowly and turn abstract words into the actual topic.
- Check that the answer really happened in the argument.
Flaw Questions Example
This is a practice example we wrote to show the idea. It is not a real LSAT question.
Argument: Each part of this machine is light. So the machine as a whole must be light.
Question: The reasoning is flawed because the argument…
Best answer: assumes that what is true of each part is true of the whole.
Why: This is a part to whole mistake. Many light parts can add up to something heavy.
Common Traps
- Answers that describe a real flaw that did not happen in this argument.
- Answers that are too strong, like “relies on a false premise,” when the premises are not the problem.
- Skimming abstract wording instead of matching it to the argument.
Common LSAT Flaws
| Flaw | What it looks like |
|---|---|
| Link treated as cause | Two things happen together, so one must cause the other |
| Necessary vs sufficient | Treating something required as if it guarantees the result |
| Part and whole | What is true of the parts must be true of the whole |
| Weak sample | A small or unusual group is used to judge everyone |
| Attacking the person | Rejecting a claim because of who said it |
| False choice | Acting as if only two options exist |
Flaw Questions FAQ
What flaws show up most on the LSAT?
Common ones include treating a link as a cause, confusing necessary and sufficient, part to whole, weak samples, and attacking the person.
Does the right answer use the same words as the argument?
Often not. It may be abstract, so translate it back to the topic.
Do I need to memorize flaw names?
Know the patterns. The test describes them in plain phrases more often than by name.
See all Logical Reasoning question types, read the Logical Reasoning guide, and practice with LSAC’s free official PrepTests.
Related LSAT Section Guides
- All LSAT section and question type guides
- LSAT Logical Reasoning guide
- Logical Reasoning question types
- LSAT Reading Comprehension guide
- Reading Comprehension question types
Many flaw answers depend on conditional logic. See our LSAT conditional logic guide.