June 2007 LSAT Question Explanations June 2007 - Sec 2 - LR...

June 2007 - Sec 2 - LR - Q15

Video Transcript:

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Question 15, a new government policy has been developed to avoid many serious cases of influenza.
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This goal will be accomplished by the annual vaccination of high-risk individuals, everyone
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65 and older as well as anyone with a chronic disease that might cause them to experience
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complications from the influenza virus.
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Each year's vaccination will protect only against the strain of the influenza virus
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deemed most likely to be prevalent that year, so every year, it will be necessary for all
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high-risk individuals to receive a vaccine for a different strain of the virus.
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First step argument or facts?
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Clearly, we have an argument.
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The conclusion is that every year, it will be necessary for all high-risk individuals
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to receive a vaccine for a different strain of the virus.
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How do we know that?
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Well, the premise is that each year's vaccination will protect only against the strain of influenza
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virus deemed most likely to be prevalent that year.
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If you notice, the structure of this argument, our premise is that each year's vaccination
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will protect only against the most prevalent strain of influenza virus.
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And from that premise, the author concludes that high-risk individuals must receive a
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vaccine for a different strain of influenza every year.
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You notice that that conclusion does not follow from that premise.
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Just because each year's vaccination will only protect against the most prevalent strain
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of influenza, that is not sufficient to conclude that high-risk individuals must receive a
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vaccine for a different strain of influenza each year.
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How do we know that one strain cannot be prevalent in multiple years?
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So this is clearly a flawed argument and as we proceed to the questions then, we see which
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one of the following is an assumption that would allow the conclusion above to be properly
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drawn.
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Allow the conclusion to be properly drawn, we have another strengthen with sufficient
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premise question.
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Again, looking for the answer choice that 100% guarantees the conclusion that high-risk
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individuals must receive a vaccine for a different strain of influenza each year based on the
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premise that each year's vaccination will only protect against the most prevalent strain
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of influenza.
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Let's take a look at (A).
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The number of individuals in the high-risk group for influenza will not significantly
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change from year to year.
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You notice (A) is completely irrelevant, we don't care how many people are in this high-risk
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group from year to year, so (A) clearly does not even strengthen so how can it strengthen
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and guarantee the conclusion?
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(A) is out.
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(B), the likelihood that a serious influenza epidemic will occur varies from year to year.
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Again, completely irrelevant.
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That does nothing to our argument.
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It definitely does not guarantee the conclusion, so (B) is eliminated.
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(C), no vaccine for the influenza virus protects against more than one strain of that virus.
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(C) is a popular answer choice among students because (C) does strengthen.
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It's basically saying that every vaccine only protects against one strain.
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That seems to strengthen the argument because you cannot get a vaccine that protects you
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against 10 different strains of influenza but you notice, it does not guarantee the
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conclusion that a new vaccine is needed every year for high-risk individuals because even
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if every vaccine only protects against one strain of influenza, how do we know that we
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cannot have a strain that was prevalent in one year also be prevalent in another year?
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(C) doesn't address that problem with this argument so (C) would be eliminated.
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Which brings me to (D).
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Each year, the strain of influenza virus deemed most likely to be prevalent will be one that
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had not previously been deemed most likely to be prevalent.
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And you notice, (D) closes the gap by telling us if you're deemed to be most prevalent in
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one year, you are not going to be deemed to be prevalent in any other year and that would
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guarantee the conclusion that high-risk individuals must receive a vaccine for a different strain
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of influenza each year, so (D) would be the correct answer, again, 100% guarantees the
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conclusion in the passage.
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Lastly, just to make sure you're checking (E), each year's vaccine will have fewer side
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effects than the vaccine of the previous year since the technology for making vaccines will
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constantly improve.
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Again, we are not talking about side effects.
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(E) is completely irrelevant so (E) is eliminated.