Reading skills among high school students in Gotham have

Question

Reading skills among high school students in Gotham have been steadily declining, which can only be the result of overcrowding in the schools.

Which of the following, if true, most seriously weakens the argument expressed above?

a) The high school system in Gotham succeeds in giving students a good education at considerably less cost than do most systems.
b) Several cities have found that overcrowding in the schools is not always associated with lower reading scores. 
c) Gotham schools have a greater teacher-to-student ratio than most other school systems.
d) Students' reading skills have not declined in other cities where the high schools are just as crowded as those of Gotham. 
e) Schools are not overcrowded in many cities where high school reading scores have declined more than they have in Gotham.

Please justify your options. I feel two options (d & e) are correct. Stimulus suggests that overcrowding in the schools (cause) leads to decline in reading skills among high school students in Gotham (Effect). 
Option d states effect does not occur even when the cause occurs. 
Option e states effect occurs even when cause has not occurred.
How do you justify one option over the other as both seem to weaken the argument.

talk2vj · Accepted Answer

Cause -> Effect

Overcrowding -> Declining in reading skills

Both options are equally attractive. But this is one slight different. It is the use of the word "crowd" vs "overcrowd". A typical shell game. D is saying that the other cities' high school do not experiene decline in the reading skill even though the schools are as crowded as those of Gotham. "Crowd" does not mean "overcrowd". It could also mean "same population" and the other cities's schools have more teachers.

E is specific about the word "overcrowd". Also, it is saying that schools that are not "overcrowded" are also experiening the same effect (i.e. decline in reading skills)

Bunuel · Answer

KAPLAN OFFICIAL EXPLANATION:

The important word in the author's conclusion is the word only. She states that the problem of declining reading skills can only have one cause: overcrowding. Anything that renders doubtful the causal connection between Gotham's overcrowding and Gotham's declining reading scores will seriously weaken the argument. (E) does this by pointing out a case in which skills have declined, yet there is no overcrowding. So something other than overcrowding can account for a decline in reading skills. (E) wins. (Note: This ties in perfectly with the logical element present in the next question.)

(A) just tries to make an excuse for Gotham schools by pointing out that they spend less money. While this may furnish a reason for the overcrowding, it does nothing to hurt the argument that the overcrowding causes declining scores.

(B) and (D) point to overcrowding without declining skills. Yet the author didn't say that overcrowding always leads to declines in skills, but rather that declines in skills are always a result of overcrowding. Be careful to keep the causal mechanism straight!

(C), if anything, strengthens the argument by pointing out that the decline in reading scores cannot be attributed to a low teacher-to-student ratio. It must, therefore, be attributed to some other cause (e.g., overcrowding).

ohfred · Answer

My thoughts:

Keyword is ONLY. i.e. Overcrowding is a necessary condition for decline in reading skills. Hence, conclusion is: If Decline, then Overcrowding.

E states: some non-overcrowded schools experience decline reading skills. It effectively means that if Decline then NOT necessarily overcrowding. Hence, weakens conclusion.

D simply says that there is no decline in reading skills for some overcrowded schools. It does nothing to the conclusion because the conclusion does not talk about the scenario when there is no decline in reading skills.

geturdream · Answer

the conclusion says the overcrowd in the school is causing the decline in the reading skills.
To weaken this one, we have to show that the overcrowd is not the only reason for the decine in reading skills.

Now in D
Students' reading skills have not declined in other cities where the high schools are just as crowded as those of Gotham. 
it says, there are other cities which are as crowded as Gotham, where the reading skills have not declined. But it doesn't give any information regarding the other reasons for the decline.

In E
Schools are not overcrowded in many cities where high school reading scores have declined more than they have in Gotham.
it says in some less crowded cities the reading skills have declined. So there has to some reason for this delcine other than the overcrowd. This one weakens the argument by introducing some other factors.

So E is the ans

amit2k9 · Answer

E says !overcrowding => reading decline.
Meaning effect occurs even if cause does not.

rohitgoel15 · Answer

Though I went with E but didnt like D and E both for the above highlighted portions that have nowhere been mentioned in the argument.

DevilDoggNC · Answer

Great question!!!!

Weakening an argument by introducing an "alternate causation"...

D is close -- but subtle differences between schools and high schools, and between reading scores and reading scores among high school students...

E wins!

manhattan187 · Answer

Pretty good explanations.

It is a cause + effect situation. To weaken it, you must "prove" otherwise in similar conditions (ex.: A place where the effect is present, i mean, the skills have also been constantly decreasing), but for any reason other than "overcrowded". It could even be a random X reason, as long as it is different than "overcrowded".

D is wrong because the effect was different.

etdenlinger · Answer

Here is the difference between D and E:

D is saying that overcrowding did not cause a decrease in reading skills among some schools. If the conclusion was overcrowding ALWAYS causes a decrease in reading skills, then this answer would be correct. However, the conclusion is that overcrowding is the ONLY cause of a decline in reading skills. E states that there must be other causes for a decline in reading skills than overcrowding. This directly addresses the conclusion.

Thus E. It boils down to the difference between ONLY and ALWAYS.

anonimo · Answer

Dude, could seem that what others cities do is out of scope. Doesn't have the answer to be a subset of the stimulus? In any other question this would be out of scope. ..

yash88 · Answer

Here, The cause is overcrowding which has resulted into declining reading skills.

Hence, if we can identify that some other cause has given resulted in declining reading skills, we can weaken the argument.
Option B says that overcrowding is not associated with lower reading scores. Hence, something else is associated with it .

Please advise, what flaw is there in this reasoning.

mvictor · Answer

clearly, all but D and E can easily be eliminated.
I chose E.
no cause -> effect still is present. thus, cause does not lead to effect.

GmatAvengers800 · Answer

Please clear my doubt

E says many cities but not all other cities, leaving a scope for some other cities similar to Gotham?

D says about all other schools that are just as crowded as Gotham, so narrowed down to the required comparison?

B says not always, meaning sometimes may be possible, same like E says ?

C is saying a different reason but that reason was not properly associated with the decline or incline in the scores, so can be skipped

A This adds no value

Sent from my Redmi 4 using  GMAT Club Forum mobile app

US09 · Answer

E.

Because in causality weakeners, we need to find if effect is present even in the absence of the said cause. A, B and C are out.

D. Students' reading skills have not declined. So, they may have increased or remained constant in schools that are as crowded as Gotham is. Close contender. But we are more concerned about schools with declining reading skills of students. Hold but check the one remaining answer choice.

E. Clearly mentions that in "many" schools, the reading scores have "declined" even without "overcrowding". Goes in line with our pre-thinking. Correct.

AliciaSierra · Answer

Which is that next question mentioned in above solution-->(Note: This ties in perfectly with the logical element present in the next question.)

Arro44 · Answer

The tags mention both Kaplan and Veritas as a source... I take it this is a Kaplan question?

lary301254M7 · Answer

I don't think this is a good question

(E) says  Schools are not overcrowded   in many cities  where high school reading scores have declined more than they have in Gotham.

Aren't we focusing on what happened in Gotham? Even though it may be true that overcrowding is not the cause in many cities, overcrowding can still be the cause in "Gotham".

Experts please chime in, thank you

KarishmaB · Answer

Reading skills have declined.
Schools are overcrowded.

Conclusion: Overcrowding is necessary for decline in skills.
The use of the word "only" shows that the author considers "overcrowding" necessary for decline in reading skills. It is our "only if" construct.
Only if overcrowding, then decline in reading skills.

We need to weaken this i.e. we need to weaken that overcrowding is necessary for decline in reading skills.

a) The high school system in Gotham succeeds in giving students a good education at considerably less cost than do most systems.

Cost is irrelevant

b) Several cities have found that overcrowding in the schools is not always associated with lower reading scores.

Overcrowding may not always lead to lower reading scores. This says that overcrowding may not be sufficient. Our argument does not worry about sufficiency. We are concerned about necessity.

c) Gotham schools have a greater teacher-to-student ratio than most other school systems.

Teacher-student ratio is irrelevant. We are talking about overcrowding - too many students in one school. We don't know the parameters on which "too many" is measured.

d) Students' reading skills have not declined in other cities where the high schools are just as crowded as those of Gotham.

Same as option (B). Overcrowding is not sufficient to cause lower reading skills.

e) Schools are not overcrowded in many cities where high school reading scores have declined more than they have in Gotham.

Shows that without overcrowding too, decline in reading skills can occur. So overcrowding is not necessary. Weakens our argument.
Note that the author is applying the principle to Gotham. We need to weaken the principle. For that we can show how it doesn't apply necessarily and hence it may not apply to Gotham either.

Answer (E)

Note: I may have worded the argument differently to make it clearer.

NeoNguyen1989 · Answer

Imo E
'Only' usage indicates that overcrowding is the necessary condition of declining scores. To weaken the conditional reasoning is to prove that overcrowding is not the necessary condition; declining scores can happen without overcrowding. E is correct.

B and D are not correct since they concern with sufficient condition of overcrowding

Posted from my mobile device

Reading skills among high school students in Gotham have

Prep Toolkit

Top 5 GMAT Debrief Videos

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards

GMAT Critical Reasoning (CR) Questions

Reading skills among high school students in Gotham have

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards