The number of people diagnosed as having a certain intestinal disease

Question

The number of people diagnosed as having a certain intestinal disease has dropped significantly in a rural county this year, as compared to last year. Health officials attribute this decrease entirely to improved sanitary conditions at water-treatment plants, which made for cleaner water this year and thus reduced the incidence of the disease.

Which of the following, if true, would most seriously weaken the health officials’ explanation for the lower incidence of the disease?

(A) Many new water-treatment plants have been built in the last five years in the rural county.

(B) Bottled spring water has not been consumed in significantly different quantities by people diagnosed as having the intestinal disease, as compared to people who did not contract the disease.

(C) Because of a new diagnostic technique, many people who until this year would have been diagnosed as having the intestinal disease are now correctly diagnosed as suffering from intestinal ulcers.

(D) Because of medical advances this year, far fewer people who contract the intestinal disease will develop severe cases of the disease.

(E) The water in the rural county was brought up to the sanitary standards of the water in neighboring counties ten years ago.

As per OG, the correct ans choice is (C). But I think ans choice (B) weighs above (C).

OG rules out choice (B) simply because it says bottled water has been consumed in approximately same quantity by 2 classes of people; those who were diagnosed and those who were not. 
Bottled water(pure water) can be considered as the best improvement of sanitary conditions at water-treatment plants. So this means the perfect improvement of sanitary conditions exposed to the two classes of people in roughly equal amount still drops the number of diagnosed people significantly. This clearly conveys that sanitary condition improvement is NOT a factor in this drop, which definitely contradicts the conclusion.

Choice (C) offers an alternate explaination (new technique proving old diagnoses wrong) for the reduction in diagnoses.

So why not choice (B), which directly contradicts the conclusion, is a better choice than choice (C), which gives an alternate explaination?

mikemcgarry · Accepted Answer

Dear  longhaul123 ,

I see that   abhimahna   answered your question, but I am going to add a few thoughts as well.

Here's (B)
B.  Bottled spring water has not been consumed in significantly different quantities by people diagnosed as having the intestinal disease, as compared to people who did not contract the disease .
First of all, the wording is very tricky. What it is saying is that: 
 People with the intestinal disease didn't drink a lot of bottled water. 
People without the intestinal disease drank a lot of bottled water .

Also, notice how you changed the logic. You spoke of " Bottled spring water that is   from the water treatment plant ." My friend, with all due respect, this is a major misunderstanding. This is an example of the real-world experience you need to answer GMAT CR questions. Water that comes from a water-treatment plant is NOT spring water. Also, by its very nature, a water-treatment plant is not a bottling facility: nothing is bottled there. A  spring  is a place where water flows up naturally from the ground: many times, this is some of the purest water one could possibly drink. Many companies (Arrowhead, Volvic, Iceland, Alhambra, Poland Springs, Crystal Geyser, etc.) bottle spring water in plastic bottles, and these plastic bottles of water are available to consumers. This is a very different source of water than the water that comes out of the  tap . Water from a water-treatment facility would be water out of the tap in people's house. Some people don't trust tap water, so they go to the store to buy bottled spring water. Other people point out that tap water is held to strict standards and bottled water isn't; also, the plastic bottles aren't healthy because they leech chemicals into the water. This has been a major debate in the USA for several years.

In order to do well on the GMAT CR, you need to read the news and be aware of issues in the real world. See: 
 GMAT Critical Reasoning and Outside Knowledge

Thus, what we learn is that the people who were drinking tap water, the water that had come from the water-treatment facility, got the intestinal disease, but the folks who avoided tap water and instead bought & drank bottled spring water did not get the disease. Thus, the source of the disease originated in the water-treatment plant. This would be a strengthener when you understand what it is saying. It's very typical for a strengthener to be a trap answer for a weakener question.

Here's (C)
 (C) Because of a new diagnostic technique, many people who until this year would have been diagnosed as having the intestinal disease are now correctly diagnosed as suffering from intestinal ulcers.

This " new diagnostic technique " corrected diagnoses.

Last year, a large number of people were diagnosed with this intestinal disease. That's part of the evidence. What is not discussed, though, in the prompt is whether they were diagnosed  correctly . That was before the " new diagnostic technique ." (C) tells us that before this " new diagnostic technique ," people were  misdiagnosed  with the intestinal disease. Thus, it could be that the high number of diagnoses of the intestinal disease was due, in part, to a large number of misdiagnoses, people who actually had intestinal ulcers, but the medical technology available at the time incorrectly ascribed their symptoms to the intestinal disease.

This also would explain why, when the " new diagnostic technique " was introduced this year, why the number of diagnoses of the intestinal disease was lower this year--with the new procedure, there was no confusion. The people suffering from intestinal ulcers were no longer misdiagnosed as having the intestinal disease.

This is a truly brilliant OA. It's not that the actual number of cases of the intestinal disease decreased at all. Instead, the drop was due to a correction of a measurement error: other diseased were being misdiagnosed as the intestinal disease, inflating the number of those cases, so when all the diagnoses were corrected, the low number of cases of the intestinal disease was more in line with reality.

Does all this make sense?
Mike :-)

rishabhmudgal · Answer

IMO c... A option was a bugger.. but u can eliminate it by using the keyword "NEW water ...." its talking about new. While in the stimulus nothing is mentioned about NEW. Took me almost 3 min to eliminate option A.
Tip: When ur stuck with two options, dont try to think which one is better but try to think which one is wrong. Find that small clue that changes the entire picture.

hardnstrong · Answer

Option B - talks about bottled water not the the improved sanity conditions at water treatment plant
In GMAT we can assume anything (even a tiny thing). only facts from premise(s) can be taken and bottled water is not mentioned in any premise. Hence, this is irrelevant.

Option C - says even after improving sanity condition at water treatment plant, intestenial disease remians in one or another form. This directly attacks the conclusion.
Hence this is the correct answer

Whether its a weaken or strengthen question, do not assume anything outside what is mentioned in the premise.

Hope this helps

vinraj · Answer

Hi,

While answering this question, I initially thought E was the answer. But after careful inspection 'E' clearly seems to be wrong. 
E says 'The water in the rural county was brought up to the sanitary standards of the water in neighboring counties 
 ten years ago '.

The original stimulus says that Health officials mentioned the reason as improved sanitary 
conditions . They clearly meant that the condition improved from last year.. ( this year sanitary condition >> last year sanitary condition)

But option E says the sanitary condition in rural county improved 10 years back. It may mean that this year sanitary condition = last year sanitary condition. This is giving unclear explanation.

Also, according to E, if sanitary conditions in rural county have really increased, then this statement is actually strengthening the health officials point instead of weakening.

Moreover, according to E, the sanitary conditions in neighboring counties might themselves have been inadequate ....

Concentrating on the words,'ten years ago', can help you eliminate answer E.

EliLTG · Answer

Always keep a careful eye for the scope of the question and each answer--that will let you eliminate tempting traps without losing time on the clock. In this case, notice how the events discussed in the prompt are "this year...compared to last year." That makes it unlikely that an answer covering all of "the last five years" will provide a satisfactory weakener.

Hope this helps!

AryamaDuttaSaikia · Answer

B - Cannot be the answer for " Weakener".

Both kinds of people - A - Diagnosed & B - Not Diagnosed - drink nearly same quantity of bottled spring water (assuming - bottled spring water is after the improved sanitary conditions at water treatment plants). This fact doesn't hit the causal conclusion.

longhaul123 · Answer

Even after going through all the explanations i am still not understanding why B must not the answer. Because option B says that the Bottled spring water that is from the water treatment plant is doing nothing to the people diagnosed with the disease and for people who have not contracted such disease. So this statement says that the water treatment plant does nothing to reduce the intestinal disorder and hence weakens the official's conclusion. 
But where as the option C talks about the new diagnostic technique which is not even present in the argument. So i choose option B. Can some expert  mikemcgarry   GMATNinja  please shed some light on this . Thank you

abhimahna · Answer

Hi  longhaul123  ,

Notice that we need to weaken what author provided as a reason for the conclusion.

B is saying there was no significant difference in the consumption of bottled water. It is actually ruling out a scenario that could be a weakener to our conclusion. It is saying what people were drinking was same throughout. Hence, I would rule out B because it is a strengthener.

Now, let's talk about C.

It is saying "Hey Man, you are wrong". There is no positive impact of sanitary conditions rather there is a new technique that has been developed and which is telling us that people were having ulcers rather than disorder. Hence, people are still the same but what was previously determined was wrong. Hence, it is a strongest weakener to what Author is saying.

Does that make sense?

gmatexam439 · Answer

The number of people diagnosed as having a certain intestinal disease has dropped significantly in a rural county this year, as compared to last year. Health officials attribute this decrease entirely to improved sanitary conditions at water-treatment plants, which made for cleaner water this year and thus reduced the incidence of the disease.

Which of the following, if true, would most seriously weaken the health officials’ explanation for the lower incidence of the disease?

A. Many new water-treatment plants have been built in the last five years in the rural county. 
 Out of scope

B. Bottled spring water has not been consumed in significantly different quantities by people diagnosed as having the intestinal disease, as compared to people who did not contract the disease.
 If the bottled spring water is consumed in same quantities by both the sufferers and non-sufferers, then this option removes the chances that there might be an alternate cause of the diseases. This is strengthener.

C. Because of a new diagnostic technique, many people who until this year would have been diagnosed as having the intestinal disease are now correctly diagnosed as suffering from intestinal ulcers.
 Correct for the stated reasons.

D. Because of medical advances this year, far fewer people who contract the intestinal disease will develop severe cases of the disease.
 This option talks about the future possibility. Out of scope.

E. The water in the rural county was brought up to the sanitary standards of the water in neighboring counties ten years ago.
 Out of scope

LakerFan24 · Answer

The number of people diagnosed as having a certain intestinal disease has dropped significantly in a rural county this year, as compared to last year. Health officials attribute this decrease entirely to improved sanitary conditions at water-treatment plants, which made for cleaner water this year and thus reduced the incidence of the disease.

Which of the following, if true, would most seriously weaken the health officials’ explanation for the lower incidence of the disease?

(A) Many new water-treatment plants have been built in the last five years in the rural county.

(B) Bottled spring water has not been consumed in significantly different quantities by people diagnosed as having the intestinal disease, as compared to people who did not contract the disease.

(C) Because of a new diagnostic technique, many people who until this year would have been diagnosed as having the intestinal disease are now correctly diagnosed as suffering from intestinal ulcers.

(D) Because of medical advances this year, far fewer people who contract the intestinal disease will develop severe cases of the disease.

(E) The water in the rural county was brought up to the sanitary standards of the water in neighboring counties ten years ago.

Show Spoiler

As per OG, the correct ans choice is (C). But I think ans choice (B) weighs above (C).

OG rules out choice (B) simply because it says bottled water has been consumed in approximately same quantity by 2 classes of people; those who were diagnosed and those who were not.
Bottled water(pure water) can be considered as the best improvement of sanitary conditions at water-treatment plants. So this means the perfect improvement of sanitary conditions exposed to the two classes of people in roughly equal amount still drops the number of diagnosed people significantly. This clearly conveys that sanitary condition improvement is NOT a factor in this drop, which definitely contradicts the conclusion.

Choice (C) offers an alternate explaination (new technique proving old diagnoses wrong) for the reduction in diagnoses.

So why not choice (B), which directly contradicts the conclusion, is a better choice than choice (C), which gives an alternate explaination?

GMATin · Answer

Pre-thinking:  Conclusion is that the lower reporting of the intestinal disease is due to improved sanitary conditions at water-treatment plants. We need to weaken this conclusion. Possible weakeners could be change in diagnostic facilities available in the county. This change (for better or for worse) could alter the number of diagnosis made in the county and thereby weaken the conclusion. Another possible weakener could be that maybe there has been an installation in most houses which treats unsafe water, thereby reducing number of people who are exposed to the disease. Or maybe lesser number of people are going to doctors when they contract such a disease and hence are not represented in the number of incidences.

Option analysis: 
A) Irrelevant. Also, we are clearly told that the decline has come due to improved sanitary conditions in the plants and not change in number of the plants itself
B) Although, a highly tempting choice, we can't confirm if bottled spring water is same as the water coming from the water-treatment plants spoken about in the question. 
C)  Correct.  Matches the prethinking
D) Irrelevant. It doesn't matter if severity of the disease has reduced or not. We are considered with number of reports
E) Irrelevant. We are not comparing the county with another county. Maybe the incidence of the disease is similarly high in both counties, hence this is incorrect

Elite097 · Answer

OE

The health officials’ explanation assumes that the decrease in the number of people diagnosed with the disease
accurately reflects a diminution in cases of the disease. By pointing out that this assumption is false, C
undermines the officials’ explanation and thus is the best answer. Since A supports the view that sanitary
conditions have been improving, it tends to support the officials’ explanation. B also tends to support the officials’
explanation, because it eliminates a factor that might have differentiated between those contracting and those
not contracting the disease and thus rules out an alternative explanation. The reduction of the severity of the
diagnosed cases does not bear on the officials’ explanation. So D is not correct. Since the standards in
neighboring counties might themselves have been inadequate, E does not weaken the officials’ explanation

Elite097 · Answer

MartyTargetTestPrep   ThatDudeKnows   KarishmaB  are the intestinal ulcers assumed to be different from intestinal diseases?  GMATNinja

MartyTargetTestPrep · Answer

Let's consider choice (C), which is the only statement to in the question that mentions intestinal ulcers.

(C) Because of a new diagnostic technique, many people who until this year would have been diagnosed as having the intestinal disease are now correctly diagnosed as suffering from intestinal ulcers.

We can see that (C) indicates that being diagnosed with intestinal ulcers is different from being diagnosed with intestinal disease. So, we can go with the idea that intestinal ulcers and intestinal disease are two different things.

Sneha2021 · Answer

Hi Experts,
 MartyTargetTestPrep   GMATNinja   KarishmaB

Which of the following, if true, would most seriously weaken the health officials’ explanation for the lower incidence of the disease?
As per my understanding, we need to weaken the "explanation" that "decrease in lower incidence is because of improved sanitary conditions at water-treatment plants". So improved sanitary condition is the not the reason for the lower incidence of the disease.
Now C is doubting on the no. of incidence but in question stem, it is mentioned clearly that we need. to weaken the reason and not the number of incidence itself. 
Please help me to understand how C is correct acc to question stem.
Thanks for your time!

MartyTargetTestPrep · Answer

Hi Sneha.

Notice that, at the beginning, the passage says, "The number of people DIAGNOSED as having a certain intestinal disease has dropped significantly."

So, the conclusion we have to cast doubt on is not about the INCIDENCE of the disease. It's about the RATE OF DIAGNOSIS.

The author concludes that the reason for this decrease in the rate of diagnosis is the improved sanitary conditions.

Then choice (C) weakens the case for the author's conclusion by bringing up the fact that "Because of a new diagnostic technique, many people who until this year would have been diagnosed as having the intestinal disease are now correctly diagnosed as suffering from intestinal ulcers."

So, we can see that (C) brings up an alternative reason for the decrease in the rate of diagnosis. In the past, people who didn't have the disease were misdiagnosed as having it, and now, because of the new diagnostic technique, fewer people are being misdiagnosed as having the intestinal disease.

KarishmaB · Answer

We are talking about a certain intestinal disease. Its name is not given and it is mentioned as "the intestinal disease" (showing that we are talking about the same disease) in options.

Number of people diagnosed with this disease has reduced significantly this year. 
Officials attribute this decrease in the number of people diagnosed to improved sanitary conditions at water-treatment plants (which supposedly led to a decrease in incidence of the disease).

How do we weaken the explanation given by the health officials (that better conditions led to lower incidence which led to a decrease in number of people diagnosed)?

(A) Many new water-treatment plants have been built in the last five years in the rural county.

We are talking about improved sanitary conditions at water-treatment plants. How many plants are there, doesn't matter.

(B) Bottled spring water has not been consumed in significantly different quantities by people diagnosed as having the intestinal disease, as compared to people who did not contract the disease.

This option tells us that consumption of bottled spring water is not a differentiating factor between people who got the disease and those who did not. So it doesn't impact the reasoning given by the officials. Both had similar amount of bottled water consumption and hence would have similar amount of water treatment plant water consumption. We are looking for a differentiating factor. This is not correct.

(C) Because of a new diagnostic technique, many people who until this year would have been diagnosed as having the intestinal disease are now correctly diagnosed as suffering from intestinal ulcers.

Better diagnostic techniques is one of the reasons for fewer people diagnosed. Then decrease in incidence because of better sanitary conditions is not solely responsible for fewer diagnosed cases. Hence, it weakens the explanation given by the officials.

(D) Because of medical advances this year, far fewer people who contract the intestinal disease will develop severe cases of the disease.

No of severe cases is out of scope.

(E) The water in the rural county was brought up to the sanitary standards of the water in neighboring counties ten years ago.

Since there is no comparison given regarding the number of cases of the disease in neighbouring counties, this option doesn't help in any way. We are comparing the number of people diagnosed in this county last year with the number of people diagnosed in this county this year.

Answer (C)

KarishmaB · Answer

You have noted a good point but note another thing:
Health officials attribute  this decrease  entirely to improved sanitary conditions at water-treatment plants, which made for cleaner water this year and thus reduced the incidence of the disease.

The highlighted is the decrease in the number of people diagnosed. So health officials would have said something like this: Fewer people have been diagnosed this year because we cleaned up the water treatment plants and hence reduced the number of cases of the disease.

So health officials gave an explanation for how they decreased the incidence of the disease (intermediate outcome) and hence reduced the number of people diagnosed (final outcome). 
We need to weaken the explanation of the intermediate outcome which itself is the explanation for the final outcome.

ArnauG · Answer

The option that would most seriously weaken the health officials' explanation for the lower incidence of the disease is option (C): Because of a new diagnostic technique, many people who until this year would have been diagnosed as having the intestinal disease are now correctly diagnosed as suffering from intestinal ulcers.

The health officials attribute the decrease in the number of diagnosed cases of the intestinal disease to improved sanitary conditions at water-treatment plants. However, option (C) introduces a new factor that weakens this explanation. It states that a new diagnostic technique has been implemented, which allows for the correct diagnosis of intestinal ulcers instead of the intestinal disease. This implies that many people who would have previously been diagnosed with the intestinal disease are now being correctly diagnosed with a different condition.

If the new diagnostic technique is responsible for reclassifying cases that would have been previously diagnosed as the intestinal disease as intestinal ulcers, then it suggests that the decrease in diagnosed cases is not solely due to improved sanitary conditions but rather a result of a change in diagnostic categorization. This weakens the link between water sanitation and the decrease in diagnosed cases of the intestinal disease.

The number of people diagnosed as having a certain intestinal disease

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GMAT Critical Reasoning (CR) Questions

The number of people diagnosed as having a certain intestinal disease

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