Q5 - Researchers announced recently that

[LSAT-Chang]

Wow.. I am so confused as to how (B) weakens the idea that "using sunscreen is unlikely to reduce a person's risk of developing such skin cancer." I was ultimately down to (B) and (E) and I didn't see how (B) related to the argument so I went with (E). Any thoughts??

[extraordinary.kye]

Answer Choice (B):
this shows that damage done years ago would still persist today, even if more people use sunscreen. In other words, it takes a generation for the effects of increased use of sunscrren to effect us..

And with answer choice (E):
doesn't weaken the argument unless we know these people still get cancer despite being protected

Hope this helps

[zainrizvi]

I picked (E) so let me try and explain why its wrong.

First, huge scope shift - most regularly are people who BELIEVE themselves to be most susceptible to skin cancer. OK? So you could have a bunch of paranoid people who lather on sunscreen - how does this weaken the argument? It doesn't.


More complicated explanation:

Now let's suppose that you made the mistake, like I did, of overlooking the "believe" part. So you have "those who use sunscreens most regularly are people who are most susceptible to skin cancer."

I think I fell into this trap because often pointing out the differences in the conditions of a group is a good weakener. In this case, it doesn't hold true.

I originally thought that if people who use sunscreens most regularly are those that are most susceptible to skin cancer, then their increased susceptibility may cover the fact that sunscreen does, in fact, protect against skin cancer. For example, their susceptibility increases their chances of skin cancer by 30% while the sunscreen reduces their chances by 15%. Sunscreen is having a measurable effect, which is being hidden by the susceptibility. HOWEVER, the stimulus says that the incidence has stayed the SAME The stimulus, then, is saying if they had a 30% chance before, and they STILL have a 30% chance. So (E) doesn't do much.

[ManhattanPrepLSAT1]

Awesome discussion here!

If you want to skip a bunch of theory and get to the question scroll down to the line break.

I think the comments above help us see the wide variety of approaches people bring to the LSAT. Little things like the difference between what people "believe" or "think" and what "is" actually the case. There are so many interesting relationships that the LSAT writer routinely exploits. The more time you spend with the LSAT the more you recognize them quickly and in their variety.

This is a great example of a highly repeated argument structure. It shows up most regularly on Strengthen, Weaken, and Explain questions, and occasionally shows up on Necessary Assumption and ID Conclusion questions. If you spot it the correct answers for each of those question types is fairly predictable.

Question Type: impact of correct answer
Strengthen: eliminate a competing explanation
Weaken: provide a competing explanation
Explain: provide any explanation at all (the stimulus essentially represents the step before an explanation is offered)
Necessary Assumption: eliminate a competing explanation
ID Conclusion: the claim that represents the explanation in the argument is paraphrased in the correct answer

____________________________________________________

Okay to the question!

extraordinary.kye's explanation of the impact of answer choice (B) is right on. The argument presents a perplexing situation (sunscreen use is up and skin cancer is too) and then offers an explanation for this (sunscreen is ineffective). Answer choice (B) weakens this by offering an alternative explanation for the strange lack of any reduction in cancer (the length of time cancer takes to materialize is longer than has the use of sunscreen been measured).

Let's look at the incorrect answers:

(A) is irrelevant. Why should they have to use only the most expensive brand?
(C) makes you want to think that sunscreen should be effective because it's based on research of someone we might consider to be knowledgable about the skin. But the dermatologists could have been wrong or the pharmaceutical companies could have messed up the product even though it was based on sound research.
(D) is irrelevant. We don't know if these people would wear sunscreen, and furthermore this would have been true 25 years ago as well as today.
(E) can be eliminated for the reason pointed out by zainrizvi. It's a great and colorful explanation that's exactly right. Just because those folks believe they're susceptible to cancer doesn't make it the case.

[shaynfernandez]

Very perplexing how this could be the 5th question. Anyway, B does not convince me of any weakness.

From what we know old people get cancer, why? Because it develops later in life because of the previous burns.... Ok so they got burnt and they have cancer because of this... So did they wear sun screen? We have no idea. How does that weaken the argument? This would require an extra assumption, that the wore sunscreen as a kid.

[tianpuzhang1990]

In this case, the conclusion is that the sunscreen does not work. The evidence is that in the past 25 years, although there has been an increasing use of sunscreen, cancer from sun burn continued to grow.

Looks reasonable, well, if more of the people use sunscreen, but at the same time more of them are getting cancer from sun burn, doesn't that prove that sunscreen does not work?

Well, not necessarily. Can it be the case that sunscreen DOES work but still more of the people are getting cancer? Sure! If cancer from sun burn is a result from childhood exposure to sun, then no matter whether sunscreen works or not, if you put it on after that "childhood" period when sun burn was already given, sunscreens will not stop one from developing that cancer!

As to whether or not it has to be assumed that the older people used sunscreens as children, I don't think this is a necessary assumption for the choice to weaken the argument. Note that if we assume that the older people did use sunscreen, and we know that more of them are developing cancer, then this choice is saying that yes sunscreen does not work, and this means the choice actually STRENGTHENS the argument! And surely we do not want that.

Hence the evidence does not prove the conclusion.

[sumukh09]

In B we're talking about people that are "very old" so are we not dealing with a small number of people relative to the general population? The rate of developing skin cancer can still be offset by people who are not "very old." I see what B is trying to get at; it's possible that suncreens can reduce the risk of skin cancer since its use was less prevalent 25 years ago and the people that developed skin cancer back then develop it yet again when they are older so its not that suncreens have been ineffective, they just can't do anything about these "older" people. But what about people that aren't so old and currently use sunscreen?

[johnscottwilsonsr]

So why not C? Assume the following... sometimes plumbers put in cheap plumbing so they will have more business when the pluming breaks.

If dermatologists were nefarious, might they not work to make a lousy product so as to grow more business from skin cancer patience? The question is not written to clarify if the dermatologists are virtuous or nefarious.

Back me up but this, but do the LSAT writers never think this way and assume everyone is virtuous unless expressly stated otherwise?

[huitungsing]

IMO, Choice B STRENGTHENS, NOT WEAKENS the conclusion that "using sunscreen is unlikely to reduce risk of cancer"

I understand the choice B is interpreted as a WEAKENER by some people, as it tells us that maybe the sunscreen can reduce risks, its just that the sunscreen might have not been used during the "young period" when it can reduce risks.

BUT doesnt that STRENGTHEN the argument as well? If the sunscreen is no longer effective when applied at an older age for the people who are exposed when young, doesnt this supports "using sunscreen is unlikely to reduce risk of cancer"

Or maybe it only STRENGTHENS a modified version of the conclusion: "using sunscreen is unlikely to reduce cancer risk WHEN USED DURING OLD". This leaves room for "using sunscreen is likely to reduce cancer risk WHEN USED YOUNG". In that case, this however WEAKENS the original conclusion again.

If that is the case THEN Choice B is the answer.

Am i thinking along the right lines?

[brandoncbias]

IMO, Choice B STRENGTHENS, NOT WEAKENS the conclusion that "using sunscreen is unlikely to reduce risk of cancer"

I understand the choice B is interpreted as a WEAKENER by some people, as it tells us that maybe the sunscreen can reduce risks, its just that the sunscreen might have not been used during the "young period" when it can reduce risks.

BUT doesnt that STRENGTHEN the argument as well? If the sunscreen is no longer effective when applied at an older age for the people who are exposed when young, doesnt this supports "using sunscreen is unlikely to reduce risk of cancer"

Or maybe it only STRENGTHENS a modified version of the conclusion: "using sunscreen is unlikely to reduce cancer risk WHEN USED DURING OLD". This leaves room for "using sunscreen is likely to reduce cancer risk WHEN USED YOUNG". In that case, this however WEAKENS the original conclusion again.

If that is the case THEN Choice B is the answer.

Am i thinking along the right lines?

B definitely doesn't strengthen the conclusion. The conclusion is about sunscreen being ineffective for reducing risk of skin cancer development. B defines the general method of skin cancer development by saying it shows up when you're older if you had sunburns while young. If this is true, the affects of the current increase in sunscreen on skin cancer prevalence won't be measurable until these people are older. The current increase in skin cancer results from people who could have already been certain to get at as they got older. Thus it undermines the claim that these increases show that sunscreen is unlikely to reduce skin cancer risk.

[steves]

On answer (E), Matt and Zainrizvi seem to actually take different approaches. Matt suggests that if the statement in (E) was more definitive (not "people who believe themselves') then (E) might have been correct--which is why I incorrectly picked it. Zainrizvi seems to go further and suggest that even a more definitive (E) could not be correct. That seems at odds with Matt's explanation. Would a definitive (E) be correct?

[rinagoldfield]

Thanks, Steves. If (E) talked about the people who ARE most susceptible to skin cancer, then it would be a good weakener. It would suggest alternate reason why people who wear sunscreen nevertheless develop skin cancer. Alternate explanations = good answer choices to weaken questions.

[kyuya]

This question was pretty tough.

Basically the argument is this:

- sun screen usage up
- cancer rates up

Therefore, sun screen doesn't work (if it did, why would cancer rates continue to rise?)

My initial thought was that perhaps cancer would continue to rise even more rapidly if sun screen were not used (looked for an assumption like that) but ultimately was not what the question wanted. Honestly, (B) is a really tough answer choice in my opinion. It may be best in this case to use process of elimination because it is much easier to rationalize why the other answers are wrong. With that being said, I'll turn to the wrong answers.

(A) This is irrelevant. People not buying the most expensive brand does not matter. I think the LSAT writers are attempting to make the reader make an assumption. The assumption (I believe) is that expensive = better, and with this assumption in mind one may think "hmm.. they got the cheap stuff so it didn't work". However, this in itself is an extra assumption that does not necessarily need to be correct. For those reasons, this answer choice is wrong.

(C) This is pretty irrelevant. Easy one to eliminate.

(D) I think this may actually strengthen opposed to weaken this argument. If people who knew they were susceptible to skin cancer stayed in, that would mean that people out in the sun are not especially prone to cancer. That would make it even more ridiculous that cancer rates continue to rise with sun screen being used along side this trend. Even despite the people not being predisposed to cancer, they are getting it. I believe that strengthens the argument!

(E) "who believe themselves" yes this is irrelevant. However, this is the answer choice I picked, I should have known this was wrong. This language itself is enough to eliminate it, because what do these people know? Their opinion is pretty meaningless.

On to the correct answer...

(B) if in the last 25 years sun screen usage has been going up, that is relatively recently (if we accept that cancer is typically among the old) then we can state that the benefits have not been incurred yet because not enough time has elapsed. Once all these youths grow old that have been using sun screen abundantly, the effects may be apparent (less old people with skin cancer due to younger burns).

[ling.75]

How can answer B help to explain the growing incidence of skin cancer?

I suppose what answer B intend to do is to indicate that old people now contributes to the growing incidence of skin cancer. But how about old people 25 years ago? Are they less likely to develop skin cancer? If everything being equal, there will always be the same amount of old people getting skin cancer.

[maryadkins]

I suppose what answer B intend to do is to indicate that old people now contributes to the growing incidence of skin cancer.

Yes. (B) raises this possibility as an explanation of why the rates have gone up. It is an alternative to sunscreen being useless.

But how about old people 25 years ago? Are they less likely to develop skin cancer?

We don't know. But we don't need to. We just need to weaken the argument here, not create an air-tight new one.