The stimulus presents an argument. We are told that there is a government agency that rates airlines, and that the highest-ranked airlines are those with the smallest proportion of late flights. The reason for this system, you are told, is "to establish an objective measure of the relative efficiency of different airlines' personnel" with respect to flight schedules.
So there is an implied connection here between airline personnel efficiency, and timeliness of flights. You can view this as a cause and effect argument. The stated cause is the efficiency of personnel. The effect is timely flights.
The question stem asks you to weaken (invalidate) this reasoning. There are three ways to weaken cause and effect reasoning. You can (1) show an alternate cause, or (2) show the cause without the effect, or (3) show the effect without the cause.
Answer choice (B) is an alternate cause: that the true cause of untimely flights is bad weather, such that the efficiency of airline personnel does not matter.
Hope this helps! Please let us know if you have any additional questions.
OhemaaJune 3, 2018
Why would (E) be wrong?
MehranJune 3, 2018
Hi @Ohemaa, thanks for your post.
As always, let's start with the stimulus. You are told that a government agency publishes airline ratings based on proportion of late flights. You are also told that the purpose of these ratings is "to establish an objective measure of the relative efficiency of airline personnel."
Right away, you should be asking, "wait, why does the timeliness of a flight necessarily tell you anything about personnel efficiency?" Think about it - flights are routinely delayed because of weather, not because of a late or inefficient flight attendant, right?
The question stem asks you to select the answer choice that would undermine the use of airline ratings based on proportion of late flights for the purpose of measuring personnel efficiency.
Answer choice (B) points out the alternative cause for lateness (bad weather) that is overlooked in the stimulus.
Answer choice (E) is irrelevant - however "late" is defined is not the issue here. The issue is - assuming that a flight is late, however "late" is defined - does that lateness show personnel inefficiency, or might there be some other cause for the delays?
Hope this helps! Please let us know if you have any additional questions.
