#16 - Airport administrator: According to the latest figures

[Administrator]

Complete Question Explanation

Flaw in the Reasoning. The correct answer choice is (B)

With reference to the Logical Reasoning section instructions—"You should not make assumptions that are by commonsense standards implausible, superfluous, or incompatible with the passage"—this question is in fact a fascinating example of the utility of using a "commonsense standard" to generate the best prephrase. To wit, the author concludes that based on the larger body of evidence from the pilot logs, there is on-balance more reason to conclude that runways may be built closer together without a significant increase in risk. To identify the flaw, one might ask, how could it be possible that even though there is more evidence from the pilot logs, the logs themselves are inferior to the air traffic control tapes?

Anticipate for your prephrase that the credited response will give you a description of a reason why the logs could be inferior to the tapes.

Answer choice (A): Does the author actually ever claim that there is a causal link between closer runways and careful pilots? No, this statement is simply not present in the stimulus and is unsupported.

Answer choice (B): This is the correct answer choice. If we are to rely on our prephrase that the correct answer choice will describe a manner in which the pilot logs are in fact inferior to the air traffic control data, we will have an excellent match for this choice. If our prephrase is in some respect lacking, you can still get this answer either by process of elimination or by matching it will the scenario described in the stimulus. Who are the people who are making the pilot logs? The pilots. What do the logs describe? How often these pilots stray off course during landing. Would it be reasonable to assume that self-reporting mistakes not be the most reliable source of information for determining how often mistakes actually occur? Certainly.

Answer choice (C): What does this choice mean? It means that the author would be attempting to discredit the air traffic control data based on the integrity of its source (a "source"or "ad hominem" fallacy). This does not match the scenario in the stimulus. The author does not question the "integrity" of the air traffic controllers. Instead, he claims that the larger body of evidence from pilot logs is what makes the logs superior evidence.

Answer choice (D): The author does not claim that the tapes are irrelevant. Rather, he claims that the tapes do not present a complete picture of the situation, that it is better to use the pilot logs because they provide more data than do the air traffic control tapes. Again, make sure the information in the answer choice is a complete match for the stimulus.

Answer choice (E): As in choice (C), a thorough knowledge of common fallacies, their structure, and how they appear in answer choices is helpful. This answer choice describes an "absence of evidence" flaw in which the author would conclude that based on the fact that the data from the air traffic controllers may not by itself be sufficient to justify a conclusion (that runways should not be built closer together), that the data themselves are inaccurate. This is not the case. The author makes no contention that the air traffic control data are flawed, only that they are inferior to the data from the pilot logs, which the author contends are more comprehensive and therefore superior.

[mkmkll]

I chose E on this question. My thought process was:

A is out of scope. The argument presented does not assume what is described in the answer choice.

I eliminate B, which is the answer choice, because I thought it was, instead of a diagnose of what flaws the argument has, an unwarranted attack on the person and the source making the argument.

C is wrong because even though the argument challenges the accuracy of evidence used to support the opposing view, it does not question the integrity of those holding the opposing view.

D is wrong because the administrator's concern was with the "partial review," not with specific flights.

I chose E because even though the administrator does not infer the higher number must be inaccurate, it does point out the unreliable nature of it simply because of a lack of conclusive evidence supporting the accuracy of it.

I've come back to this Q many times now and still can't see why B is correct.

Thank you so much!!
mk

[Kristina Moen]

Hi mk,

Welcome! The author gives us two numbers:
1 commercial flight in 2 million strays off course - based on study of flight reports required by all pilots
1 commercial flight in 20,000 - based off partial review of air traffic control tapes

The author concludes that the second is relatively unreliable compared to the first number, and so the number is low enough to allow runways to be built closer together without a significant increase in risk. The author is comparing the two numbers. He is saying that the first number is more reliable than the second number.

Answer choice (B) starts off with "overlooks the fact..." and then gives us a new fact. You should ask yourself if that fact is enough to cast doubt on the argument. Here, the fact presented is "those who make mistakes are often unreliable sources of information about those mistakes." The first number is based off flight reports. Who creates the flight reports? It is required of pilots - the very people who would be making the errors in landing! So who's to say they aren't fudging the numbers a little?

Hope that helps.

[mkmkll]

Hi Kristina,

Thank you so much for the explanation, which really helped me understand why B is correct. But what about E? I'm still unable to find the reason that is convincing enough to kill E.

Thanks!
mk

[lunsandy]

Hi Powerscore,

When I was doing this question in my PT, I thought the flaw of the argument was "absence of evidence flaw" because of "partial review of air traffic control tapes and so is relatively unreliable compared to the other figure." I thought because it was a "partial review" the airport admin is saying the lack/ or partial of an evidence is enough to show that the opponents are wrong and what I (airport admin) am saying about flight reports is correct. I see why B is the correct answer, but I still find E very tempting.

Is E incorrect because it says "higher number's accuracy that it must be inaccurate" since our stimulus only tells us "relatively unreliable?" Thus, we don't know if the airport admin thinks the opponents are wrong/ inaccurate, we just know that the airport admin thinks the flight reports from pilots are better? If, the argument did say "partial review of air traffic control tapes and so is WRONG compared to the other figures" would that make an "absence of evidence" flaw?

I guess I am struggling to spot how to tell it is an absence of evidence flaw from the flaw in B where the pilots could have vested interest in making the reports reliable.

Thanks a lot!

[Luke Haqq]

Hi lunsandy,

To see why (E) can't be the right answer, take a look at the language that comes towards the end of that answer choice: "The argument infers from a lack of conclusive evidence supporting the higher number’s accuracy that it must be inaccurate."

The italicized part is what ultimately is problematic with (E). The airport administrator doesn't claim that the second figure must be inaccurate. Rather the administrator concludes that it is "relatively unreliable compared to the other figure." (E) is therefore too strong to describe a flaw in the argument.

Hope that helps!

[deck1134]

Hi Powerscore,

I went through iterations of the above when I did this question, but thought that Like's point was moot: isn't "relatively unreliable" the same as "inaccurate"

[freddythepup]

Hi, I read through all the posts for this question. My reason for choosing D and then E when I tried it again is because D says the air traffic control tapes is not "accurate information", which I figured is the same as the stimulus saying the air traffic control tapes is "unreliable". And then when I tried it again, I picked E because E says the higher number's evidence is not conclusive to make it accurate, which I again thought was a better alternative for the stimulus's equivalent of "unreliable" information. Can you please explain why I shouldn't assume both choices' language is equivalent to "unreliable" used in the stimulus?

Another reason why I crossed out B both times I tried the question is because I thought B is too extreme since it claims that pilots make mistakes so they are unreliable. I thought since the given probabilities are so low (Both numbers) can we assume that pilots often make mistakes and hence their source is not reliable? Or should I just accept the wording in choice B as another way to say (as mentioned above) that when we self report something, we might be wrong?

[origamicaptain]

I'm still not seeing how B is correct. It seems like it is adding information out of scope with the stimulus. I can just as easily say that self-reported pilots have more of an incentive to maintain their reputation.

I chose E because a larger sample size doesn't mean that the data itself is accurate in comparison to the other data source.

[Brook Miscoski]

Deck,

Luke's point is correct. Commonly, "reliable" means that a study is trustworthy, whereas "accurate" means that a study is correct. The administrator is not claiming that the 1/20,000 is inaccurate, he is saying that it involved less data and so is less likely to be correct--it is less reliable.

Another way to eliminate (E) is to notice that the stimulus draws its conclusion by arguing that one data set is superior, and the reasoning has nothing to do with whether there is conclusive evidence.