Logical reasoning PrepTest 124 · Section 1 · Question 18

Incorrect. The conclusion is that three years' experience is a requirement to success, not that it's sufficient. Therefore, it absolutely considers the possibility that there will be some people who still aren't successful even after three years—after all, it's just a requirement.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Errors in Reasoning

Stimulus Summary:
Successful salesperson → Establish strong client base
Studies: At least three years establishing client base → Successful salesperson
Therefore - Successful salesperson → At least three years

Answer Anticipation:
There are two hints as to the flaw in this argument. The first is that it relies on a study, which suggests a sampling flaw and a correlation/causation flaw. The second is conditional language ("it is certain", "must", "anyone"), suggesting a conditional logic flaw.

Looking at the study, there's no hint that the sample was skewed or too small (it's not really discussed at all), so we shouldn't expect that flaw. The results of the study are also a correlation, not a causal relationship, so a correlation/causation flaw is unlikely, as well.

Moving to the conditional logic flaw, we can see that the necessary condition of the conclusion—that a successful salesperson has at least three years experience—is a sufficient condition in the premise. There, spending three years building a client base is said to be sufficient to "mak[ing] a comfortable living" in sales—i.e., being successful. This illegal reversal is the flaw in the argument, so the correct answer is likely to address it.

We could end our Anticipation there, but the question stem actually gives us a hint as to how the answer choice is going to be phrased. It asks not just to highlight how the argument is vulnerable to criticism, but specifically notes that it's because the argument fails to consider a given possibility. In switching three years experience from a sufficient condition to a necessary one, the argument is therefore overlooking the possibility that a salesperson can build up that strong client base that'll guarantee their success in fewer than three years.

Answer Explanation:
This answer addresses the argument's switch of three years experience from a necessary to a sufficient condition, and it even matches our more specific anticipation. The argument establishes a strong client base as being sufficient to success, and it concludes that success comes after at least three years. However, it could be the case that some can build that base in under three years, as this answer states.

Key Takeaway:
Some Errors in Reasoning question stems provide additional information as to how the correct answer is going to be phrased. These will generally fall into two camps—it'll state that the argument is flawed because it overlooks some possibility, or because it makes an assumption. If you've been working at the LSAT a bit, you may note that this mirrors introductory phrasing of answer choices in some other Errors in Reasoning questions, and that's correct!

Incorrect. In concluding that three years of experience is necessary for success, the argument absolutely considers that some people without that necessary condition for success won't end up being successful.

Incorrect. The language discussing the three-year period always says "at least" three years, so it considers that it may take longer than that.

Incorrect. The argument doesn't care how frequently these requirements/conditions are met, so whether "few" or many salespeople can afford to spend this time building a client base is out of scope.