LSAT Explanation PT 20, S4, Q14: Advertisement: A leading economist has determined

LSAT Question Stem

Which one of the following identifies a reasoning error in the argument? 

Logical Reasoning Question Type

This is a Flaw question. 

Correct Answer

The correct answer to this question is C. 

LSAT Question Complete Explanation

Let's first analyze the argument in the passage. The passage presents an advertisement that states that among people who used computers at their workplace, those who also owned portable ("laptop") computers earned 25 percent more on average than those who did not. The advertisement concludes that owning a laptop computer led to a higher-paying job. In this argument, the premise is the observation about people who owned laptops earning more, and the conclusion is that owning a laptop leads to a higher-paying job.

The question type is Flaw, and it's asking us to identify the reasoning error in the argument.

To understand this better, let's use a simple example. Suppose we observe that people who wear expensive clothes are more successful in their careers. It would be incorrect to conclude that wearing expensive clothes causes career success. There could be other factors at play, such as education, experience, or even the possibility that career success allows people to afford expensive clothes.

An "Evaluate" question for this argument could be, "Is there any other factor that could explain the higher earnings of people who own laptops?"

Now, let's discuss each answer choice:

a) This answer choice suggests that the argument is based on a small sample size, but the passage does not indicate that the sample size is limited. The observation is made among people who used computers at their workplace, which could be a large number of people.

b) The conclusion does not merely restate a claim made earlier in the argument. Instead, the conclusion is a causal relationship (owning a laptop leads to a higher-paying job), while the premise is a correlation (people who own laptops earn more).

c) This is the correct answer. The argument concludes that owning a laptop causes a higher-paying job, but the evidence provided is consistent with the reverse causality: a higher-paying job could lead to owning a laptop. The passage does not establish a clear causal relationship between owning a laptop and earning more.

d) This answer choice is incorrect because the information provided in the passage does not show that the conclusion is false. The information supports the conclusion but fails to prove it.

e) This answer choice is incorrect because the passage does not project currently existing trends indefinitely into the future. The conclusion is about what happened in the past.

In conclusion, the correct answer is C, as the argument fails to establish a clear causal relationship between owning a laptop and having a higher-paying job. The evidence given is consistent with the reverse causality, but the passage concludes that owning a laptop led to a higher-paying job.