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#7 - More pedestrian injuries occur at crosswalks marked by

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Complete Question Explanation

Flaw in the Reasoning—#%, CE. The correct answer choice is (A)

Here, the stimulus author considers the higher number of pedestrian injuries that occur at crosswalks “marked by both striping on the roadway and flashing lights” compared to the number of injuries that occur at crosswalks that are not marked in that way and, presumably, are less heavily marked. Because of the greater number of injuries at the more heavily marked crosswalks, the author concludes that the “so-called safety features are a waste of taxpayer money.”

For an argument to properly rely on a comparison between two things, those things must actually be similar. In this argument, the author treats the crosswalks as being identical, other than for the presence of safety features at some crosswalk that are missing from the others. This “sameness” relied on by the author necessarily includes the assumption that the crosswalks are inherently equally dangerous. But we are given no reason to think the crosswalks are the same. To the contrary, there may be some reason that some of the crosswalks have more safety features than the others. Perhaps the reason is that the crosswalks with the safety features are inherently more dangerous. In that case, the safety features could provide some benefit in reducing the number of pedestrian injuries, yet there still could be more pedestrian injuries occurring at the crosswalks with these features.

The question stem establishes this as a Flaw in the Reasoning question. Our prephrase is that the correct answer choice will describe the failure by the argument to consider the possibility that the crosswalks with the safety features are inherently more dangerous than the other crosswalks. And, that danger, though mitigated by the safety features, produces the higher number of accidents.

Answer choice (A): This is the correct answer choice. As discussed above, the argument treated the crosswalks as if they all involved the same risk to pedestrians, when there was some reason, i.e., the increased safety features at the more dangerous crosswalks, to conclude they were different.

Answer choice (B): Assuming, as did the stimulus author, that the crosswalks are essentially the same other than the provision of safety features, the evidence was not that the safety features fail to reduce the number of injuries, but rather that more injuries occur when the safety features are present.

Answer choice (C): The argument does not mention replacing the current safety features with any other devices, let alone less expensive ones.

Answer choice (D): The argument does not presume that the named safety features are the only safety features at the crosswalks.

Answer choice (E): While it is true that the argument does not consider this comparison between injuries to pedestrians and injuries to the occupants of cars, that comparison is irrelevant to the conclusion. It is not a logical flaw to ignore information irrelevant to the conclusion.
DAthenour
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Hi Powerscore,

I correctly chose A on this question, but was slightly tempted/intrigued by B on my Blind Review. Could you elaborate more on where exactly B goes wrong? To me, in the above explanation, failing to reduce the number of injuries could be synonymous with more injuries occurring?


Thanks for your help!
Francis O'Rourke
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Hi DAthenour,

Answer choice (B) is rather broad. It states that the speaker made a conclusion concerning all safety features or that this belief was a necessary assumption of the conclusion. Since this argument only concerned two specific types of safety feature, we do not know if the speaker necessarily assumes that every safety feature is a waste of money.
JD180
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Francis O'Rourke wrote:Hi DAthenour,

Answer choice (B) is rather broad. It states that the speaker made a conclusion concerning all safety features or that this belief was a necessary assumption of the conclusion. Since this argument only concerned two specific types of safety feature, we do not know if the speaker necessarily assumes that every safety feature is a waste of money.


The explanation given here I believe, is fallacious. I will clear it up and then provide what I think is the correct explanation:

You're missing something at the end there when you said that we do not know if the speaker necessarily assumes that every safety feature is a waste of money - There's a big gap. Correctly stated you should say:

We do not know if the speaker necessarily assumes that every safety feature THAT DO NOT REDUCE THE NUMBER OF INJURIES is a waste of money. The fact that you neglected this makes the explanation you gave moot. I will explain why B is not the answer below:

Breakdown of stimulus: leaving the crosswalk without striping and flashing lights would confer X amount of injuries. When you take the same crosswalk, and put striping and flashing lights, it would confer X+Y injuries (more injuries); this is what the stimulus states.

Thus safety measures that increase the amount of injuries relative to a regular cross walk, according to the author, are a waste of taxpayer money.

Now we can see that B is not the answer - why? Well, B says that the author thinks its a waste of money when safety features fail to reduce the number of injuries. No, the author does not think this. If there were 0 more injuries (aka the striping/stoplights has no change in injuries compared to the regular crosswalk), yes you failed to reduce injuries, but the injuries did not increase. The author thinks that only when you INCREASE injuries, its a waste of money (obviously).The author could very well think that failing to reduce injuries (specifically, no change in injuries) is TOTALLY fine and not a waste of money, AS LONG AS The stoplights/striping DONT INCREASE the number of injuries.

Any flaws?

Hope that clears things up.
Dave Killoran
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Hi JD,

I agree that "the fail to reduce" portion of the answer choice is key here, and Francis was a bit fast and loose on the reply. I'll probably alter his response a bit when I get a chance in order to avoid any confusion from future readers.

Thanks!
Dave Killoran
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