LSAT Explanation PT 25, S4, Q11: Taken together, some 2,000 stocks recommended

LSAT Question Stem

Each of the following, if true, weakens the argument EXCEPT: 

Logical Reasoning Question Type

This is a Weaken question. 

Correct Answer

The correct answer to this question is D. 

LSAT Question Complete Explanation

The argument in the passage states that over a 12-year period, 2,000 stocks recommended on a popular television show by the show's guests, who are mostly successful consultants for multibillion-dollar stock portfolios, performed less successfully than the market as a whole. Based on this, the argument concludes that no one should ever follow any recommendations by these so-called experts. The structure of the argument is as follows:

Premise: The 2,000 stocks recommended on the television show performed less successfully than the market as a whole for the past 12 years.

Conclusion: No one should ever follow any recommendations by these so-called experts.

An "Evaluate" question for this argument would be: "Is the performance of the recommended stocks an accurate representation of the expertise of the show's guests?"

Now, let's analyze each answer choice:

a) Taken together, the stocks recommended on the television show performed better than the market as a whole for the past year.

This answer choice weakens the argument because it provides a scenario in which the experts' recommendations performed better than the market as a whole, even if it was just for one year. This contradicts the conclusion that no one should ever follow any recommendations by these experts.

b) Taken together, the stocks recommended on the television show performed better for the past 12-year period than stock portfolios that were actually selected by any other means.

This answer choice weakens the argument by suggesting that the experts' recommendations were actually better than other stock portfolios selected by different means, which contradicts the conclusion that no one should ever follow any recommendations by these experts.

c) Performance of the stocks recommended on the television show was measured by stock dividends, whereas the performance of the market as a whole was measured by change in share value.

This answer choice weakens the argument by pointing out that the performance of the recommended stocks and the market as a whole were measured using different methods, which makes the comparison between them unfair. This undermines the conclusion that no one should ever follow any recommendations by these experts.

d) Performance of the stocks recommended on the television show was measured independently by a number of analysts, and the results of all the measurements concurred.

This answer choice is the correct answer because it does not weaken the argument. Instead, it strengthens the reliability of the evidence (the performance of the recommended stocks) by stating that multiple analysts independently agreed on the results. This answer choice does not undermine the conclusion or the relationship between the premises and the conclusion.

e) The stock portfolios for which the guests were consultants performed better for the past 12-year period than the market as a whole.

This answer choice weakens the argument by suggesting that the guests' expertise was successful in other contexts, which contradicts the conclusion that no one should ever follow any recommendations by these experts.

In summary, the correct answer to this Weaken EXCEPT question is answer choice D, as it does not weaken the argument, while all other answer choices do.