Let's re-word practice question 2 as "A recent survey shows that 77 percent of people feel that crime is increasing and that 87 percent feel the government should be handing out free cell phones. Therefore, the government must firmly address the rising crime rate." This illustrates why choice B is correct. "Presumes, without providing justification, that there is a correlation between free cell phones and a high crime rate".

The argument states that a group of people BELIEVE in both those statistics. Just because people believe in support of something, does not mean that they are correct, which makes D correct

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Course: LSAT > Unit 1

Lesson 6: Logical Reasoning – Articles

Identify a flaw | Learn more

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How do we identify flaws?

The Logical Reasoning section includes a number of questions that ask you to identify a weakness in an argument’s reasoning. You’ll be presented with an argument that is flawed in some way. Your task? To describe why the argument isn’t sound.

How do we recognize Flaw questions?

In Flaw questions, you’ll see:

A full argument in the passage, with a main conclusion and supporting evidence.
Choices that contain descriptions of different flaws.

Questions of this kind are worded in a variety of ways:

The reasoning in the argument is flawed because the argument

The argument commits which one of the following errors of reasoning?

The argument’s reasoning is questionable because the argument fails to rule out the possibility that

The reasoning above is most vulnerable to criticism on the grounds that it

Top tip: Pay attention to the end of the question. Some Flaw questions will actually give you some “bonus language” at the end of it—for instance, the third example above ends with, “the argument fails to rule out the possibility that”. This clue tells you to be on the lookout for a possibility that the arguer has overlooked. This is a specific kind of flaw, so you already have more information than you would have if the question asked “Which one of the following errors of reasoning does the argument commit?”

You should assume that the argument is defective in some way. Your job is to figure out how, and to select the choice that accurately describes an error or weakness.

Flaw: A reasoning error or defect; a feature of an argument's reasoning that keeps the argument from delivering the degree of support that it claims to deliver for its conclusion.

The flaws you’ll see on the LSAT include unstated assumptions, logical errors, overly-confident deductions based on insufficient empirical evidence, and rhetorical tricks that masquerade as arguments.

What’s the difference between Identifying a Flaw and Identifying a Weakener?

When you’re asked to identify a weakener, you’re essentially finding information in the choices that makes the argument worse than it currently is.
When you’re asked to identify a flaw, you’re not adding any information but rather simply describing why the argument as it stands isn’t logically strong. In other words, the argument is already unsound.

Sometimes, to identify a flaw you'll need to identify a way in which you could weaken the argument! Take this simple example:

I know it’s going to rain tomorrow, because I heard a forecast for rain on my favorite radio station.

If your task were to Identify a Flaw, you could predict, “‘A problem is that the arguer assumes that the radio station is accurate in its forecasts.”
If your task were to Identify a Weakener, you could predict, “I’m looking for a choice that shows that the radio station isn’t always accurate in its forecasts.”

In other words, having a questionable assumption can make an argument flawed, and attacking that assumption would weaken the argument.

Example

The proportion of fat calories in the diets of people who read the nutrition labels on food products is significantly lower than it is in the diets of people who do not read nutrition labels. This shows that reading these labels promotes healthful dietary behavior.

The reasoning in the argument above is flawed in that the argument

(A) illicitly infers a cause from a correlation

(B) relies on a sample that is unlikely to be representative of the group as a whole

(C) confuses a condition that is necessary for a phenomenon to occur with a condition that is sufficient for that phenomenon to occur

(D) takes for granted that there are only two possible alternative explanations of a phenomenon

(E) draws a conclusion about the intentions of a group of people based solely on data about the consequences of their behavior

How might we approach this question?

✓ Identify the conclusion and support.

A good way to start Flaw questions, as with many other argument-based question types, is to identify the conclusion and the support.

Conclusion

Reading nutrition labels promotes healthful dietary behavior

because

Support

The proportion of fat calories in the diets of people who read the nutrition labels on food products is significantly lower than it is in the diets of people who do not read nutrition labels.

In every flaw question, something goes wrong when the arguer moves from the support to the conclusion, so it’s a great idea to separate the two parts of the argument.

Top tip: Don’t question the evidence itself. The accuracy of the support isn’t up for debate on the LSAT, so you must assume that it is true. Ask yourself, “Given that support, why can’t we arrive at the conclusion that the arguer seems so confident about?” In other words, the support may be true, but does it demonstrate that the conclusion must also be true?

✓ Do a quick check for common flaws.

A good next step is to check to see if the argument commits any common fallacies.

To recognize these:

1) Familiarize yourself with common flaw types 2) Always be on the lookout for common flaws’ indicators in an argument’s language and content.

Some classic LSAT flaws are discussed in our indispensable Types of Flaws article.

Are there any common fallacies in our example argument?

The argument draws a causal conclusion: reading nutrition labels causes healthful dietary behavior. Is this claim of causation justified by the support?

Whenever an argument claims something caused something else, ask: “Is there a good reason to believe in this causation, or is the arguer simply taking two events that happen together and trying to link them?”

To infer causation from correlation is an easy mistake for arguers to commit, and the LSAT sometimes tests your ability to recognize when it’s happening!

In our example, the arguer does indeed infer from a mere correlation (the fact that the label-readers have more healthy eating habits) a causal relationship (that label reading caused them to eat more healthy foods). The reason a causal relationship can’t necessarily be inferred is that there might be other explanations for why label-readers have healthier diets: for example, maybe people who have healthier diets to begin with happen to be more prone to reading labels to make sure they’re still on track.

So our answer prediction could be: “The arguer assumes an unjustified causal relationship between two attributes: healthy eating and label-reading.”

✓ “What if?” If you don’t find a common fallacy, describe the disconnect between the conclusion and the support in your own words.

Some arguments are flawed, but not in a common way that’s easy to categorize. In these cases, your job is to articulate the flaw in your own words, and then look for the answer you’re predicting among the choices.

We did recognize a common flaw here, but let’s suppose we hadn’t. A good way to brainstorm is to look for what-ifs. The goal is to figure out how the conclusion could be false even if all of the support is true. In this case, can you think of a hypothetical in which the study results are misleading?

What if… fat is actually good for you?

What if… the label-readers eat less fat but more sugar?

What if… the people who read labels happen to make healthier choices, but not because they read labels?

Notice that these what-ifs are stated in very simple terms. It can be helpful to pretend that you’re on the opposite side of a debate than the passage’s arguer and imagine that the what-ifs are your rebuttal.

Sometimes, students make the mistake of attempting to think about the flaw in abstract, complex language because they know that many choices in flaw questions are abstract and complex. But it’s much easier to let the test be abstract and complex while you work in simple, easy-to-understand terms.

✓ Consider assumptions

Another way to structure your thinking is to ask yourself: Is the argument making any assumptions?

Yes—several!

It assumes that the people who ate a larger proportion of fat ate more fat overall
It assumes that eating more fat is not healthy
It assumes that it is the label-reading, and not something else about them, and that causes label-readers to eat healthier.

If you can identify assumptions like these, take a moment to think about how they’re likely to be described among the choices. Take, for example, the assumption that eating less fat is healthier. It could be described in a variety of ways:

The argument assumes, without providing justification, that less fat is healthier.
The argument takes for granted that less fat is healthier.
The argument overlooks the possibility that eating more fat isn’t necessarily less healthy.
The argument fails to consider that eating less fat might not be healthier.

Notice that the assumption can be described positively or negatively: that X is true, or that the opposite of X is false. So be on the lookout for either formulation when you’re anticipating an assumption.

✓ Identify the choice that matches your prediction; otherwise, eliminate strategically.

When you have a strong prediction like the one we made above, you can often scan the choices without reading them in full until you find the match for your prediction. The stronger and more confident your prediction, the faster this process generally is.

Below, you can click on the explanation that corresponds to the choice that you believe matches our prediction, or you can read each explanation to see if your evaluation of that choice is similar to ours.

(A) illicitly infers a cause from a correlation

This is a match for our prediction! On Test Day, we could stop right here and save a lot of time. If we’re confident, we won’t have to work through choices (B) through (E) at all. Confidence comes with practice!

We predicted that the arguer takes a correlation (two things that happen at the same time) and jumps to the conclusion that one thing actively causes the other.

(B) relies on a sample that is unlikely to be representative of the group as a whole

This is a classic flaw type, but it isn’t happening here. The speaker is just discussing people in general—no specific sample set is mentioned. An example of an argument that demonstrates a sampling flaw is: Parent: My children can’t stop playing with Star Wars figures, which shows that this country’s youth are obsessed with Star Wars

(C) confuses a condition that is necessary for a phenomenon to occur with a condition that is sufficient for that phenomenon to occur

Like (B), this choice describes a classic flaw type, but not one that’s happening in this argument. We can eliminate it because this argument doesn’t contain any necessary or sufficient conditions. An example of an argument that exhibits (C)'s flaw is: You need to be 18 or older to vote. My neighbor is 19, so she must have voted.

(D) takes for granted that there are only two possible alternative explanations of a phenomenon

This choice describes something that isn’t actually happening in the argument. The speaker never brings up any alternative explanations of a phenomenon, much less two. In fact, the speaker essentially disregards the possibility of any alternative explanations of the correlation between healthy eating and label reading, by concluding that a causal relationship must be at work.

Summary

✓ Identify the conclusion and support

✓ Do a quick check for common flaws

✓ If you don’t find a common fallacy, describe the disconnect between conclusion and support in your own words

✓ Identify the choice that matches your prediction; otherwise, eliminate strategically

Common Incorrect Choices

Absent classics These choices describe classic flaws, but they just aren’t happening in the argument
True statement, not relevant These choices describe possibilities that are indeed being overlooked, but they are possibilities that would have no effect on the strength of the reasoning’s support for the conclusion anyway.

Bad assumptions Choices that ascribe an assumption to the arguer that’s inaccurate (the arguer isn’t making that assumption at all), or too strong (the arguer isn’t assuming something that’s as extreme as what is described in the choice)

Top tip: Recognize the many phrasings of a flaw. A flaw can be described as an unwarranted assumption, as an overlooked possibility, as a confusion of two things, or as the name of a classic flaw, to list just a few of the many possibilities. Don’t cling to one phrasing of a flaw, because you could miss the answer if you do! The following flaws, while distinct in wording from each other, are all conceptually identical:

The arguer assumes without warrant that X is the only possible cause.
The arguer overlooks the possibility that X is not the only possible cause.
The arguer confuses a condition that’s sufficient to bring about a certain phenomenon with a condition that’s necessary to bring about that phenomenon.

Your turn

practice question 1

Journalist: Newspapers generally report on only those scientific studies whose findings sound dramatic. Furthermore, newspaper stories about small observational studies, which are somewhat unreliable, are more frequent than newspaper stories about large randomized trials, which generate stronger scientific evidence. Therefore, a small observational study must be more likely to have dramatic findings than a large randomized trial.

Which one of the following most accurately expresses a flaw in the journalist's reasoning?

(Choice A)
It casts doubt on the reliability of a study by questioning the motives of those reporting it.
(Choice B)
It fails to consider that even if a study's findings sound dramatic, the scientific evidence for those findings may be strong.
(Choice C)
It confuses a claim about scientific studies whose findings sound dramatic with a similar claim about small observational studies.
(Choice D)
It overlooks the possibility that small observational studies are far more common than large randomized trials.
(Choice E)
It fails to rule out the possibility that a study's having findings that sound dramatic is an effect rather than a cause of the study's being reported on.

Let’s break the journalist’s argument down:

Conclusion

A small observational study must be more likely to have dramatic findings than a large randomized trial

because

Support

Newspapers generally report on only those scientific studies whose findings sound dramatic, [and]
Newspaper stories about small observational studies, which are somewhat unreliable, are more frequent than newspaper stories about large randomized trials, which generate stronger scientific evidence.

Can you detect a gap in this argument?

The journalist cites a higher frequency of stories about small studies as proof that those small studies must be more likely than large trials to have dramatic findings (since newspapers only run stories about studies that have dramatic findings). That’s a pretty big jump, to pick one necessary condition (dramatic findings) for running a story and believing that more stories about small studies means that those small studies must meet that one necessary condition more than large studies do.

Can you sum up this issue in your own words?

As with most Flaw questions, you can describe the same flaw in a number of ways:

The journalist assumes that more stories about small studies means that these small studies meet one necessary condition better than large studies do.
The journalist overlooks the possibility that maybe there are more stories about small studies simply because there are more small studies being done.
(More generally), the journalist overlooks the possibility that there could be some other reason (or many other reasons!) that more stories are run about small studies, but arbitrarily picks the “dramatic findings” without considering anything else.

Which choice matches our prediction?

practice question 2

Editorial: A recent survey shows that 77 percent of people feel that crime is increasing and that 87 percent feel the judicial system should be handing out tougher sentences. Therefore, the government must firmly address the rising crime rate.

The reasoning in the editorial's argument is most vulnerable to criticism on the grounds that the argument

(Choice A)
appeals to survey results that are inconsistent because they suggest that more people are concerned about the sentencing of criminals than are concerned about crime itself
(Choice B)
presumes, without providing justification, that there is a correlation between criminal offenders being treated leniently and a high crime rate
(Choice C)
fails to consider whether other surveys showing different results have been conducted over the years
(Choice D)
fails to distinguish between the crime rate's actually rising and people's believing that the crime rate is rising
(Choice E)
presumes, without providing justification, that tougher sentences are the most effective means of alleviating the crime problem

Let’s look at the structure of the editorial’s argument:

Conclusion

The government must firmly address the rising crime rate

because

Support

A recent survey shows that 77 percent of people feel that crime is increasing and
87 percent feel the judicial system should be handing out tougher sentences.

Can you detect any gaps in this argument when you look at the evidence and then try to discern a “jump” to the conclusion?

We can see one gap between what the surveys ask and what the editorial concludes: both of the survey responses are based on what people feel. Then the editorial concludes that the government must firmly address the rising crime rate. What rising crime rate is that? It isn’t sound logic to assume a truth about reality based on a survey on what people feel.

Can you find a choice that describes this flaw?

A few final thoughts on Flaw questions

You’re a step ahead of the arguer! Tell yourself before reading the passage that you know something the arguer doesn’t: you know up front that the argument isn’t sound. That allows you to read with the purpose of finding a disconnect between the evidence and the conclusion.
Get specific: Try not to get distracted by how abstract some of the choices in Flaw questions can be. If the wording is very vague, try replacing some of the general terms with specific terms from the passage. For example, “The arguer assumes that one event is necessary for another event to take place” can be re-thought of as, “The arguer assumes that eating fewer calories is necessary to losing weight.”
Make up your own flawed arguments: If you want to get really strong in identifying flaws, you can practice creating your own arguments around the classic flaws, or listening for flaws around you. Can you find an example of a someone committing the flaw of an unrepresentative sample when you listen to advertisements? Can you make up your own argument for causation versus correlation?
Mind the gap! Often, you’ll find that the arguer addresses one thing in the evidence and then jumps to another thing in the conclusion. The more subtle the jump is, the more challenging it is to identify the flaw. Don’t make the same assumption that the arguer does—try to “zoom out” and see the big picture without jumping to conclusions. For example, if you were faced with the argument, “I need to get a job because I need to make money”, it could be difficult because common sense tells us that this is a fairly reasonable statement. But logical sense should have us asking, “Is it necessary to get a job in order to make money? Or are there other potential ways to make money?” Think critically!

Good luck out there!

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Heavy Duty
Posted 7 months ago. Direct link to Heavy Duty's post “Let's re-word practice qu...”
Let's re-word practice question 2 as "A recent survey shows that 77 percent of people feel that crime is increasing and that 87 percent feel the government should be handing out free cell phones. Therefore, the government must firmly address the rising crime rate." This illustrates why choice B is correct. "Presumes, without providing justification, that there is a correlation between free cell phones and a high crime rate".
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- kiankashefi1
  Posted 7 months ago. Direct link to kiankashefi1's post “The argument states that ...”
  The argument states that a group of people BELIEVE in both those statistics. Just because people believe in support of something, does not mean that they are correct, which makes D correct
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