#10 - Dentist: Five recently conducted studies all show that the proportion of children

[Administrator]

Complete Question Explanation

Strengthen. The correct answer choice is (E).

The argument relies on a comparison between the teeth of European children and children in the United States: European children have relatively healthier teeth (in terms of decayed, missing, and filled teeth) than U.S. children.

It concludes that fluoride in water (which the U.S. has and Europe does not) does not have a substantial tendency to prevent tooth decay.

The argument misses that there could be all kinds of other differences between European and U.S. children's dental health that could contribute to these data. Maybe European children eat foods more conducive to dental health. Or maybe European children have better access to dental care. Or maybe European children are better about following personal dental care regimes like brushing their teeth and flossing. If any of these things were true, THAT could be the reason European children are doing better than U.S. children. And, importantly, in those circumstances, it could still be true that fluoride in water has a substantial tendency to prevent tooth decay, just not enough to overcome those other things that U.S. children are doing worse at (having bad diets, or not having access to dentists, or not following personal tooth care regimens like brushing/flossing).

To strengthen the argument we need to look for an answer choice that gets rid of one of these possibilities, thus making the comparison between European and U.S. children a better comparison. In other words, we need to find an answer choice that says one of these alternative factors is NOT all that different between European and U.S. children.

Answer choice (A): The availability of toothpaste with fluoride in the U.S. and Europe tells us nothing about whether children in Europe and the U.S. are actually using the toothpaste, and without that information, we cannot determine answer choice A's impact on the argument. Thus it is irrelevant as stated, and incorrect.

Answer choice (B): Answer choice B is talking about a different form of fluoride use than that in the conclusion (which is specifically about fluoride in water). More importantly, answer choice B says nothing about dental practice in Europe, so it cannot shed any light on the argument's comparison between European and U.S. children. Thus it is irrelevant and incorrect.

Answer choice (C): Like answer choice A, answer choice C as stated doesn't give us enough information to understand the impact on dental health of European and U.S. children. How is the hygiene taught in both Europe and the U.S. (similarly or differently)? How well do children apply the lessons they're taught in both Europe and the U.S. (well or poorly, similarly or differently)? Without knowing more, answer choice C does not shed light on whether the comparison in the stimulus is good or bad. Thus it is irrelevant as stated, and incorrect.

Answer choice (D): Answer choice D weakens the argument. It raises one of the possibilities the argument forgot about, a potential difference between Europe and the U.S. that could by itself account for European children's better dental health. In doing so, answer choice D creates the possibility that fluoride in water could be improving U.S. children's dental health, but not enough to overcome the bad results of their fewer visits to the dentist. Simplifying, in an argument that relies on a comparison between European children and U.S. children, an answer that introduces a difference between them hurts the argument.

Answer choice (E): This is the correct answer choice. Answer choice B perfectly fits our prephrase. It gets rid of a possible factor, diet, that could by itself make European children have better dental health. By getting rid of that possible difference between Europe and U.S. children, it strengthens the comparison the conclusion relies on, and makes it more likely that fluoride isn't really doing anything for U.S. children's teeth. In evaluating answer choice E, it may also be useful to imagine the scenario if the opposite of answer choice E were true. If the diets of children in the U.S. were generally worse for teeth than those of children in Europe, then it could be that the fluoride in U.S. water does help prevent tooth decay, but not enough to overcome the bad diets of U.S. children. The opposite of answer choice E would thus weaken the conclusion. This makes it a promising answer choice to strengthen the argument!

[alicechoi86@gmail.com]

I mistakenly chose (D) here, instead of the correct answer (E).

I read the dentist's argument's conclusion as: fluorination of water (F) does NOT have substantial tendency to prevent tooth decay (PTD).
I re-phrased this cause-and-effect, where the effect PTD is NOT caused by F:
C E
NOT-F PTD

In order to STRENGTHEN this, I thought about what could reinforce NOT-F (fluorination NOT being the cause of preventing tooth decay).
(D) which provides an alternate cause of children in Europe receiving more frequent dental checkups (and therefore NOT fluorination) seemed to fit the bill.

I eliminated (A), (C), (E) for not exhibiting a difference between children in Europe and the U.S. ("both the U.S. and Europe", "both Europe and the U.S.", "in the U.S....not generally worse...than in Europe").

Can anyone share any insight on why (E) is the correct answer here, and perhaps what I might be getting wrong in my analysis?

[atierney]

Hi Alice,

Yes, I would be happy to walk you through this. Firstly, the cause and effect relationship here is Fluoridation of water , the Cause, and the Prevention of tooth decay is the Effect .

So, it's FW ----> NTD. Or at least, that's what we'd like to believe; HOWEVER, we have evidence from our friends in Europe that this relationship isn't exactly as clear cut as we may think. The argument goes on to show that in America, tooth decay is not prevented with the posited cause, and that in Europe, tooth decay is actually better prevented without the posited cause. So, essentially, the argument proceeds by positing a causal relationship, showing that both the cause is not present in at least one instance where the effect is, as well as an instance in which the effect is not present where the cause is, and therefore concluding that this is "convincing evidence" that the posited causal relationship does not actually exist.

Now, to a certain extent, I'm just rephrasing what you've already done. But I think the important point here is to realize what type of answer choice we are looking for to strengthen the argument so stated. The comparison rendered leaves us with two situations: the cause not working to lead to an effect and the effect, desired, being achieved without the cause. In order to strengthen this argument, we would need to look for an answer choice that would assist in either weakening the overall relationship between fluoride in water and prevention of tooth decay (remember, this is primary CE relationship for the stimulus itself) OR assists in bolstering the two ways in which we've already weakened the argument, Cause - No Effect (in America) and No Cause - Effect (in Europe).

In considering Answer choice D, we see that there is an alternative factor to consider with respect to the causal relationship, mainly the number of dental check ups. Now dental check ups are presumed to be another cause to preventing tooth decay. Hopefully this fact is relatively obvious; however, it certainly is an alternative factor not mentioned in the stimulus, and if you think about what its role might be, well, it's pretty obvious you don't go to the dentist for just the pain of drills! (maybe?....). So basically, we have a conflicting factor. And the question we're left with is how much this factor conflicts. Which has a more determinative effect in preventing tooth decay... fluoride or going to the dentist. Could it be possible that the reason Europeans have less tooth decay because of the dental visits notwithstanding any effects otherwise by fluoride in the water? It's tough to say, probably even if you were an expert in the field, and so it definitely doesn't clarify the extent to which the absence of the original cause plays a role in Effect observed in Europe. Likewise, the extent to which Americans have greater tooth decay as compared to the Europeans might be due to the absence of this mitigating factor, rather than the feebleness of the posited cause. All things considered, hopefully, it is clear that answer choice D does not strengthen the argument.

Now, with respect to E however, this is pretty much the reverse of answer choice D, in that, rather than providing a conflicting factor in favor of the Effect (prevention of tooth decay), we have something that attempts to explain the lack of effect observed in America notwithstanding the posited causal relationship. Here, the fact that Americans eat more sweets may more than make up for whatever positive effects the fluoride in the water may have in terms of preventing tooth decay. Thus, it is the correct answer.

Let me know if you have further questions on this.

[bella243]

Could someone please comment on whether my reasoning is correct?

prephrase: make it more likely that FW doesn't substantially prevent too decay.

A) So what? The conclusion is about fluoridated water, and for A to work we need to assume that EU kids use toothpaste with fluoride.
B) So what? We already known that US water had fluoride and extra fluoride doesn't help strengthen the conclusion.

The way I see E as a correct answer is that if negated, it weakens the conclusion. "The diets of US kids are generally worse for teeth than those of children in Europe." If this is true, then it weakens the conclusion because water with fluoride might be working after all but not as well because of the poor diet.

But what exactly do C and D do to the argument? I struggled to understand how these two affect it.

Please help me understand this!

[rohangandhi97]

Why is B wrong?

[Adam Tyson]

Bella, your analysis is great, and I really like the way you used a version of the Negation Technique on the correct answer to see how it helps. We generally teach that approach only for Assumption questions, but it can be very enlightening when applied to both Strengthen and Weaken answers, as you saw here.

Basically, the argument is that because kids in the US get fluoride in the water and kids in Europe do not, and because kids in the US tend to have worse teeth than European kids, the fluoride isn't helping. This argument overlooks the possibility that fluoride might be helping and that the difference could be caused by something else (like diet). If we wanted to weaken this argument we would say something that shows another cause for the tooth problems in the US, such that fluoride might be helping a bad situation from being even worse. And to strengthen, we say the opposite - there is NOT some alternate factor that fluoride is helping to counteract. Children's teeth would not be worse in the US without fluoride in the water. Answer E does that by eliminating diet as a possible alternate cause for the different outcomes.

rohangandhi97, answer B doesn't help make the argument better because it doesn't give us any additional reason to believe that fluoridated water is unhelpful. In part this is because answer B has nothing to do with fluoride in the water, but is instead about another source of fluoride. It's also not helpful because it doesn't tell us anything about the difference between the US and Europe. Do European dentists also apply fluoride directly to teeth? Without knowing what they do, this answer can't strengthen a claim that is based on comparing the two groups. For B to have any impact, we would need to know more, and it would need to be about the water.

[sarah_tucker@alumni.brown.edu]

Why is C a wrong answer? I read both E and C as eliminating other factors for bad teeth between Europe and the US. To me, it seemed that both used a similar approach. What makes E better than C?

For C, I thought that it was eliminating the possibility that the US had worse dental hygiene in general than Europe.

[sbose]

Hi there,

I was also confused why E was a better answer than C. I initially eliminated both E and C for this reason but then during blind review I picked E.

I thought that while the children are being taught good dental hygiene (answer choice C), they may not necessarily have good dental hygiene. Alternatively, E tells us more definitively that American and European children have similar diets so we can have more confidence in the similarity between the two countries versus C.

Would that be appropriate reasoning to use for picking E over C?

Thank you in advance!

[Adam Tyson]

I think you've got it there, sbose. Being taught dental hygiene doesn't mean that kids will use that information, or use it correctly. Also, is it taught the same way in both places? Without knowing more about the programs in both places, and without knowing anything about whether children actually use the information to help improve their dental health, answer C just doesn't do much either way. It's passive and neutral, not as powerful and direct as answer E, which identifies a possible alternate cause and eliminates it.

I hope that answers it for you as well, Sarah!

[mkarimi73]

Could I have an explanation as to why (A) is incorrect? Thanks.