Sufficent vs Necessary Assumption LR Questions: PrepTest 7, Section 1 Question 2

    • July 14, 2016 at 6:33 pm #2251

      The question stem here uses the phrasing, “in order for the conclusion…to be properly drawn…” From this I assumed that the question was a Sufficient Assumption and looked for an answer that would completely justify the conclusion. But after looking through the answers, no such answer was listed. As it turns out, the right answer is something one would expect to find had the question stem asked for a Required/necessary assumption question. But this answer did not cover the larger flaw, which was that studies about mice do not necessarily pertain to humans.

      Is this common that the question stem language for necessary and sufficient assumption type questions is interchangeable? Is it that “to be properly drawn” does not necessarily indicate a sufficient assumption question? Any help would be much appreciated, thanks.

    • July 15, 2016 at 1:57 pm #2255
      LSAT Dan

      This is actually a necessary assumption question. I can a see where the “to be properly drawn” language threw you, but the word “must” in the question stem is critical. This is easier to see if you use subject matter that you’re familiar with:

      Q. In order for you to become an attorney, which of the following must occur?

      (A). You pass the bar exam.

      Notice that despite the “In order for you to become an attorney” language, this is getting at a necessary condition, not a sufficient one. Passing the bar doesn’t guarantee that you’ll be an attorney, but failing it guarantees that you won’t.

      Similarly, if the product is going to be safe (at least on the questionable argument’s reasoning), that 25-can limit can’t be hit.

      You’re correct in observing that the question is flawed apart from that (or, in more parallel language), it embodies a second necessary assumption – that something carcinogenic for mice is also carcinogenic for humans in the same relative quantity. But the presence of a second necessary assumption doesn’t change the fact that the one the answer choices give you is also a necessary assumption. Hope this helps.

      Notice that in the similarly worded sufficient assumption questions, the wording is typically something like, “Which of the following, if assumed, allows the conclusion to be properly drawn.” There’s no “must.” That “must” is like requires, or depends – it’s necessary assumption language.

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