- PowerScore Staff
- Posts: 8917
- Joined: Feb 02, 2011
- Sat Jan 21, 2012 12:00 am
#36508
Complete Question Explanation
Flaw in the Reasoning. The correct answer choice is (D)
This stimulus introduces a letter to the editor complaining of the reasoning in a recent article on
speed limits. In that article, it was noted that areas with lower speed limits had lower vehicle fatality
rates. But the letter writer concludes that it will not be that way for long, based on the fact that
vehicle-related fatalities are increasing in areas with lower speed limits.
The question stem asks why the reasoning in the letter writer’s argument is flawed. Whenever we
see simple numbers comparisons, we should be wary of the author’s tendency to draw unwarranted
conclusions. The problem here is that a simple increase in the number of vehicle related fatalities
does not provide sufficient evidence to logically draw any conclusions about whether these fatalities
are attributable to the lower speed limits. If we are seeking to determine whether or not safety is
increased by lower speed limits, a more relevant comparison would be between the respective
fatalities of high vs. low speed limit areas.
Answer choice (A): Reliance upon empirical evidence cited in the original article is not a fl aw in
the letter writer’s argument—it is quite common on the LSAT to see two different viewpoints or
interpretations based on the exact same evidence. The author of the letter is not refuting the evidence
provided by the original report, but rather the interpretation of that evidence, so this answer choice is
incorrect.
Answer choice (B): The term “often” is extremely vague, and provides no insight into the relative
likelihood of fatalities at high speeds vs. low speeds. The reason the conclusion in the stimulus
is fl awed is that it rests on a shaky premise, not that it fails to consider all outside evidence. This
answer choice does not provide an effective attack on the stimulus’ reasoning.
Answer choice (C): The fact that some drivers don’t want to drive any faster plays no role in the
editorialist’s argument, since an increased speed limit would not require anyone to drive faster. The
fact that some don’t wish to drive faster is irrelevant, and certainly does not represent a fl aw in the
author’s reasoning, so this answer choice should be eliminated.
Answer choice (D): This is the correct answer choice. If vehicle fatality rates are increasing
everywhere, not just in the low speed limit areas, then we cannot logically draw any justifiable
conclusions about the increase in fatality rates that has taken place in the low speed limit areas, and
raising the speed limit based on these figures would not necessarily be advisable.
Answer choice (E): The letter writer does provide some evidence (though questionable) against the
opposing viewpoint—the evidence that the vehicle fatality rate is increasing in the low speed limit
areas. This evidence may be weak, but the claim is presented, so this answer choice is inaccurate and
incorrect.
Flaw in the Reasoning. The correct answer choice is (D)
This stimulus introduces a letter to the editor complaining of the reasoning in a recent article on
speed limits. In that article, it was noted that areas with lower speed limits had lower vehicle fatality
rates. But the letter writer concludes that it will not be that way for long, based on the fact that
vehicle-related fatalities are increasing in areas with lower speed limits.
The question stem asks why the reasoning in the letter writer’s argument is flawed. Whenever we
see simple numbers comparisons, we should be wary of the author’s tendency to draw unwarranted
conclusions. The problem here is that a simple increase in the number of vehicle related fatalities
does not provide sufficient evidence to logically draw any conclusions about whether these fatalities
are attributable to the lower speed limits. If we are seeking to determine whether or not safety is
increased by lower speed limits, a more relevant comparison would be between the respective
fatalities of high vs. low speed limit areas.
Answer choice (A): Reliance upon empirical evidence cited in the original article is not a fl aw in
the letter writer’s argument—it is quite common on the LSAT to see two different viewpoints or
interpretations based on the exact same evidence. The author of the letter is not refuting the evidence
provided by the original report, but rather the interpretation of that evidence, so this answer choice is
incorrect.
Answer choice (B): The term “often” is extremely vague, and provides no insight into the relative
likelihood of fatalities at high speeds vs. low speeds. The reason the conclusion in the stimulus
is fl awed is that it rests on a shaky premise, not that it fails to consider all outside evidence. This
answer choice does not provide an effective attack on the stimulus’ reasoning.
Answer choice (C): The fact that some drivers don’t want to drive any faster plays no role in the
editorialist’s argument, since an increased speed limit would not require anyone to drive faster. The
fact that some don’t wish to drive faster is irrelevant, and certainly does not represent a fl aw in the
author’s reasoning, so this answer choice should be eliminated.
Answer choice (D): This is the correct answer choice. If vehicle fatality rates are increasing
everywhere, not just in the low speed limit areas, then we cannot logically draw any justifiable
conclusions about the increase in fatality rates that has taken place in the low speed limit areas, and
raising the speed limit based on these figures would not necessarily be advisable.
Answer choice (E): The letter writer does provide some evidence (though questionable) against the
opposing viewpoint—the evidence that the vehicle fatality rate is increasing in the low speed limit
areas. This evidence may be weak, but the claim is presented, so this answer choice is inaccurate and
incorrect.
