Q25 - The number of airplanes

[wj097]

Hello, chose (D) over (E), but do not have 100% confidence eliminating (E); the reason being, wouldn't disappearance of info only happening in limited places (large airports) allude that there might be 3rd factor common only among those particular places that are causing this disappearance? Despite this I eliminated (E) thinking that this 3rd factor actually is anticollision equipt planes only shuttling among large airports...

Thx

[sumukh09]

You would have to make an additional assumption about large airports being the third factor in order to justify E) and generally if you have to do more work in justifying an answer choice it is typically incorrect. Also, you know that it is a causation problem so the aim is eliminate the chain of causation or have a third factor introduced that could plausibly account for the causation. Something about "large airports" being the third factor could fall into the latter category but the link is too vague for it to work. This is just my take and I'm sure someone from Manhattan would be able to provide a more thorough explanation but I think their underlying reasoning would be the same.

[bbirdwell]

I think that's a great explanation!

(D) introduces something that we can easily see has an immediate effect on the causation here.

(E) introduces something that seems to be related, but isn't clear because the size of the airports involved has not been mentioned as a factor. Therefore, this would require additional assumptions to make it relevant, and on that basis we can eliminate!

[Nina]

i initially hesitated D and E, and eliminated D for the reason that in the stimulus it is said it has become "increasingly common" for key information to disappear after the anticollision device has been equipped, but it doesn't rule out the possibility that the sudden disappearance of key information could have happened before, just not that ''common".

any help will be appreciated!

[sumukh09]

i initially hesitated D and E, and eliminated D for the reason that in the stimulus it is said it has become "increasingly common" for key information to disappear after the anticollision device has been equipped, but it doesn't rule out the possibility that the sudden disappearance of key information could have happened before, just not that ''common".

any help will be appreciated!

You want to try and avoid reading into the stimulus like that otherwise things that shouldn't matter will begin to cause you confusion when they should not really be considered. What we know is that after they installed this new device it has become more common for information to disappear. How common this happened before the installation of the new device is irrelevant. The fact that it's happening now at an increasing frequency is what matters and D) weakens the causal link by showing effect without cause. Hope this helps

[WaltGrace1983]

I'll add the wrong ones!

(A) This absolutely doesn't matter. We want to know what other effects that anticollision devices have had/haven't had. We want to know about the connection between the device and the disappearance of key information.

(B) This actually strengthens the argument by bolstering the correlation! This shows that WHEN the information BEGAN disappearing, the device was there (Disappearing → Device Present) & (~Device Present → ~Disappearing). This really strengthens!

(C) Who cares what will happen a few months from now? We want to know about what has been occurring and why.

[AdenB248]

Ac D just says "Key information." Who says thats the key info about speed and altitude?