Critical Reasoning

Guidebook writer: I have visited hotels throughout the country and have noticed that in those built before 1930 the quality of the original carpentry work is generally superior to that in hotels built afterward. Clearly carpenters working on hotels before 1930 typically worked with more skill, care, and effort than carpenters who have worked on hotels built subsequently.

Which of the following, if true, most seriously weakens the guidebook writer's argument?

A. The quality of original carpentry in hotels is generally far superior to the quality of original carpentry in other structures, such as houses and stores.
B. Hotels built since 1930 can generally accommodate more guests than those built before 1930.
C. The materials available to carpenters working before 1930 were not significantly different in quality from the materials available to carpenters working after 1930.
D. The better the quality of original carpentry in a building, the less likely that building is to fall into disuse and be demolished.
E. The average length of apprenticeship for carpenters has declined significantly since 1930.


you can refer to the OA in OG but somehow the explanation is a bit convoluted.plz help.

sandeep1306 wrote:Guidebook writer: I have visited hotels throughout the country and have noticed that in those built before 1930 the quality of the original carpentry work is generally superior to that in hotels built afterward. Clearly carpenters working on hotels before 1930 typically worked with more skill, care, and effort than carpenters who have worked on hotels built subsequently.

Which of the following, if true, most seriously weakens the guidebook writer's argument?

A. The quality of original carpentry in hotels is generally far superior to the quality of original carpentry in other structures, such as houses and stores.
B. Hotels built since 1930 can generally accommodate more guests than those built before 1930.
C. The materials available to carpenters working before 1930 were not significantly different in quality from the materials available to carpenters working after 1930.
D. The better the quality of original carpentry in a building, the less likely that building is to fall into disuse and be demolished.
E. The average length of apprenticeship for carpenters has declined significantly since 1930.


you can refer to the OA in OG but somehow the explanation is a bit convoluted.plz help.

The argument presents a phenomenon (hotels before 1930 have better carpentry than buildings after 1930), and concludes that the cause of the phenomenon is the carpenters - The carpenters before 1930 were better. The way to weaken such a causal argument is to find another cause - another explanation as to why the carpentry is better in hotels before 1930, an explanation that does NOT say that the carpenters were better, but provides some other reason.

So if it's not the better carpenters, what else could explain the better carpentry in hotels before 1930?


D presents such an explanation for the phenomenon: better carpentry in an old hotel means less chance of the building falling into disuse and demolished - i.e. better carpentry increases the chances of the building still remaining a hotel to this day. If only the hotels with the best carpentry remain as hotels, this will explain why the old hotels still around seem to have better carpentry - it's a biased sample, composed only of the cream of the crop of the era. The carpenters before 1930 could have the same range of capabilities - good, bad or ugly - as today, and we would still be looking only at the finest level of carpentry of the era today.

took me 2:02 to reach the answer by POE. D does not crop up at first look. Agree that its a difficult question. Great explanation by Geva.

Thanks Geva!!

Nice explanation!!

Geva, thanks for the wonderful explanation. I have posted my reasoning in Bold. Could you please help me if I am wrong?
A. The quality of original carpentry in hotels is generally far superior to the quality of original carpentry in other structures, such as houses and stores (not relevant as stimulus talks only about hotels; hence this is out of scope or OOO).

B. Hotels built since 1930 can generally accommodate more guests (number of guests not relevant as stimulus doesn't talks about this, hence this is OOO) than those built before 1930.

C. The materials available to carpenters working before 1930 were not significantly different in quality from the materials available to carpenters working after 1930 (same material quality Strengthens rather than Weaken, implying despite the quality of material being same in both periods, its Carpenter's skill which is causing the difference in quality).

E. The average length of apprenticeship for carpenters has declined significantly since 1930 (length of apprenticeship may have something to do with Skills. So, this statement Strengthens rather than Weaken the conclusion).

D. The better the quality of original carpentry in a building, the less likely that building is to fall into disuse and be demolished.
Q: Isn't the better quality of carpentry due to Carpenters hence, this Strengthens the conclusion rather than Weakening? I agree this is better than other choices, but could you please point out if I am missing something? I was just wondering if we had a close competitor choice, I would have sacrificed this for any slightly better one.

Why B is wrong?

It is possible that more guess make the carpenter work degrade more quickly though the skills of the carpenter are the same.

so B is correct

Please, help, expert.

duongthang wrote:Why B is wrong?

It is possible that more guess make the carpenter work degrade more quickly though the skills of the carpenter are the same.

so B is correct

Please, help, expert.

Interesting point, but a bit of a reach. I think the bottom-line reason that this reasoning fails is that the argument talks about the quality of the carpentry, not the state of the carpentry. A piece of carpentry can be of excellent original quality, and can be recognized as such even if it is in a state of disrepair due to the repeated trampling by insensitive, loud, American guests.

rishijhawar wrote:Geva, thanks for the wonderful explanation. I have posted my reasoning in Bold. Could you please help me if I am wrong?
A. The quality of original carpentry in hotels is generally far superior to the quality of original carpentry in other structures, such as houses and stores (not relevant as stimulus talks only about hotels; hence this is out of scope or OOO).

B. Hotels built since 1930 can generally accommodate more guests (number of guests not relevant as stimulus doesn't talks about this, hence this is OOO) than those built before 1930.

C. The materials available to carpenters working before 1930 were not significantly different in quality from the materials available to carpenters working after 1930 (same material quality Strengthens rather than Weaken, implying despite the quality of material being same in both periods, its Carpenter's skill which is causing the difference in quality).

E. The average length of apprenticeship for carpenters has declined significantly since 1930 (length of apprenticeship may have something to do with Skills. So, this statement Strengthens rather than Weaken the conclusion).

D. The better the quality of original carpentry in a building, the less likely that building is to fall into disuse and be demolished.
Q: Isn't the better quality of carpentry due to Carpenters hence, this Strengthens the conclusion rather than Weakening? I agree this is better than other choices, but could you please point out if I am missing something? I was just wondering if we had a close competitor choice, I would have sacrificed this for any slightly better one.

Generally speaking, fine. I would beware of hsatily using the term "out of scope", as even the right answer choice presents new concepts not mentioned in the stimulus (i.e disuse and being demolished). At the end of the day, A and B do not weaken the argument - they don't provide an alternative explanation for the phenomenon).

As for D, you're right - better quality indicates better carpentry. But we cannot from D infer that ALL the carpenters before 1930 were better than ALL the carpenters after 1930, which is the argument's conclusion. D still weakens by pointing out that the old buildings we're considering are a biased sample composed of only those who had the best carpentry, and thus presumably the best carpenters. So yes, THESE buildings had the best carpenters working, but we cannot infer from this biased sample generally speaking carpenters were better then.

13 seconds. I had seen something similar regarding consignment clothing. You can't make an equivalent comparison when you may only be looking at the ones that last.

Geva@MasterGMAT wrote:

duongthang wrote:Why B is wrong?

It is possible that more guess make the carpenter work degrade more quickly though the skills of the carpenter are the same.

so B is correct

Please, help, expert.

Interesting point, but a bit of a reach. I think the bottom-line reason that this reasoning fails is that the argument talks about the quality of the carpentry, not the state of the carpentry. A piece of carpentry can be of excellent original quality, and can be recognized as such even if it is in a state of disrepair due to the repeated trampling by insensitive, loud, American guests.

Geva, Thank you a lot.
You mean it is possible that the quality of carpenter works is good despite the repeated trampling. That is right. But The action which increases the doubt is enough to be a weakener. The weakener dose not need to destroy the argument. So B is still correct.
I agree with you that D is more close to the " quality" evidence of argument and so more correct. But I see no clear reason to rule out B. More trampling POSSIBLY is more degrading and POSSIBLY lower quality. We do not need ABSOLUTELY. POSSIBLY is enough to increase doubt and to make a weakner.

This question hinges on a logical concept of "survivorship bias".

Why is it required that mutual fund performance presentation include all the accounts, including the "quit" ones? Same issue.