Harley1980
Homeowner Representative: Statistics show that burglars often target houses that appear unoccupied. Therefore, when homeowners are away from their homes for several days, we recommend that they leave lights on, to give the impression that the house is occupied.
Crime Expert: The same lights continuously on all night long with no change give a potential burglar a clear signal that the house is unoccupied.
The Crime Expert uses which of the following techniques in responding to the Homeowner Representative?
A) calling into question an unstated assumption
B) pointing out an undesired effect of a recommendation
C) presenting new evidence that calls the conclusion into question
D) explaining that a reputed effect is actually a cause
E) demonstrating that the conclusion is true, but not for the reasons cited
Dear
Harley1980,
I'm happy to respond.

As usual, it warms the cockles of my heart to see a question I wrote posted here on GC.
So, this is an interesting one. The homeowner person first states the fact, the evidence that burglars target houses that appear unoccupied. Then, the homeowner person suggests a plan of action, leaving the lights on, which this person thinks will convince burglars that the house in unoccupied.
The crime expert doesn't introduce any new evidence, because evidence is an objective fact to which everyone would agree. He gives his interpretation of how a burglar would respond to a house with lights continuous on, and in his interpretation, there is an undesirable effect of this action.
There's no unstated assumption pointed out, so
(A) is not right at all.
There's no confusion of cause & effect, so
(D) is not right at all.
The two people don't agree, so
(E) is not right at all.
The tricky trap answer is
(C). You see, what the Crime Expert says does not count as "evidence" in GMAT terms. Evidence is something we all could read in the newspaper or look up in a reference book, an objective fact on which there is general agreement. Now, what the Crime Expert said could be objective true. Maybe if we went out and surveyed thousands of burglars ("
Excuse me, sir, are you a burglar? I have a few survey questions to as you."), then we could gather objective evidence and call this position a fact. There is no attempt, in the course of the prompt argument, to advance such claims. The crime expert is giving us his opinion. Now, this is an opinion informed by his years of experience in the field, so it much more valuable and weighty than the opinion of a non-expert. Nevertheless, it fails short of the high mark that the GMAT holds for "evidence."
This leaves the OA,
(B), which hits the nail on the head.
Does all this make sense?
Mike