Group 13 Question 61: According to the city supervisor, the reason...

I don't see any reason why we should compare to last year. maybe there was no sidewalk at all last year? the sidewalk was constructed just prior to this winter. In my opinion, this is not necessarily the case.

I think B is best. If b is wrong, than there might be other reasons why sidewalk cracked. and it would weaken the claim.

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Foreheadson

B is the assumption and answer
C support conclusion

The answer is B. This assumes that extreme cold weather is the only reason the sidewalk would crack (besides poor materials). It is totally possible that the sidewalk cracks under milder temperatures as well. The author takes this fact for granted.

C is out of scope. Last year's temperatures are not relevant to this argument.

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Official Explanation:

According to the city supervisor, the reason that we have seen so much sidewalk cracking in the last year is because of weather conditions. This is almost certainly not the case since we’ve had a particularly mild winter. The actual cause is the shoddy materials used for sidewalk construction.

Which of the following is an assumption on which the argument relies?

(A) The city supervisor has a reason to obscure the actual reason for the sidewalk cracking.
(B) Unseasonably cold weather is the only weather condition that leads to sidewalk cracking.
(C) Temperatures during the last winter were warmer than at any time in recent years.
(D) The materials used for sidewalk construction differ from those used in the past.
(E) The unusually large amount of sidewalk cracking began during the last winter.

Question Type: Assumption
Boil It Down: It must be the case that the sidewalk cracking was caused by shoddy sidewalk materials and not weather conditions because we’ve had a particularly mild winter.
Goal: Find the most logical assumption by bridging the gap between conclusion and evidence.

Analysis:

Most arguments follow a very similar structure: the premise (or sometimes called evidence) assumption conclusion. Right now we are missing the middle; the assumption.

Evidence: We have had a particularly mild winter.
Assumption: ???
Conclusion: It must be the case that the sidewalk cracking was caused by shoddy sidewalk materials and not weather conditions.

So, when I say “bridge the gap,” I mean figure out how the evidence proves the conclusion. In this case, we have a classic case of mismatched terms between evidence and conclusion. Look again at our evidence and conclusion. The evidence says “winter,” but the conclusion says, “weather conditions.” This is a subtle yet important distinction to make because it shows where an assumption is. An assumption the author is making must be between winter and weather conditions. To find our answer, we need to connect winter and weather conditions. For example:

Evidence: We have had a particularly mild winter.
Assumption: A mild winter is not a weather condition which can cause sidewalk cracking.
Conclusion: It must be the case that the sidewalk cracking was caused by shoddy sidewalk materials and not weather conditions.

When we add our information, does it make the author’s argument more likely to be true? If the answer is yes, then we have our prediction for our answer. Remember, necessary assumption questions have almost an infinite amount of ways they could be worded, unlike a sufficient assumption question, which only has one answer. But more than likely our answer will bridge the gap between a mild winter and the weather conditions causing sidewalk cracking.

(A) The city supervisor has a reason to obscure the actual reason for the sidewalk cracking.
Does this make our conclusion that shoddy sidewalk materials, and not the mild winter, caused the sidewalk cracking more likely to be true? The answer is no. This is a tricky question because it wants you to make an assumption yourself: the city supervisor is lying because he or she does not want people to know the poor materials caused the cracking. But always remember, you should not make assumptions in the answers, and if you do, they should be minimal. Think about it a different way, is it necessary for our conclusion that the supervisor is lying? Is that a required assumption? No, it is not.

(B) Unseasonably cold weather is the only weather condition that leads to sidewalk cracking.
This answer should already look good based on our prediction earlier, but let’s plug it in to show why this answer is correct:

Evidence: We’ve had a particularly mild winter.
Assumption: Unreasonably cold weather is the only weather condition that leads to sidewalk cracking.
Conclusion: It must be the case that the sidewalk cracking was caused by shoddy sidewalk materials and not weather conditions.

Does this make the conclusion more likely to be true? The answer is yes. A clever reader may think: “but it hasn’t proven the conclusion has it? We know the winter could not have caused it, but isn’t it a jump from claiming the winter can not have caused it to the only possible cause being the materials?” If you thought this, you are absolutely correct. However, a necessary assumption question does not require us to prove the conclusion, only to find an assumption that makes the conclusion more likely to be true. We will tackle proving the conclusion 100% in sufficient assumption questions, but not here.

(C) Temperatures during the last winter were warmer than at any time in recent years.
How does this help prove our conclusion? What if last year, where temperatures were warmer in the winter, a record-breaking amount of sidewalk cracking occurred? This answer, without more, cannot help prove our conclusion. It needs to relate the weather and sidewalk cracking.

(D) The materials used for sidewalk construction differ from those used in the past.
So what if they differ? Do we know anything about the previous materials? What if the new materials caused much less cracking than the older materials? Wouldn’t that hurt our argument? This does nothing to bridge the gap between our evidence and conclusion.

(E) The unusually large amount of sidewalk cracking began during the last winter.
As with most wrong answers, this answer choice wants you to assume, but you should not make assumptions in an answer choice. Yes, an unreasonably large amount of sidewalk cracking may have occurred last winter, but do we know what the temperature was last winter? What if last winter was also a very mild winter? Wouldn’t that destroy our argument? This answer choice, on its own, does not bridge the gap.


Final Thoughts:
Some students struggle with necessary assumption questions because they have difficulty determining what the conclusion of the prompt is, and what the evidence is. It is very hard to determine an assumption without knowing what evidence is being used to come to the conclusion. If this is the case, then I would recommend practicing only ‘main point’ questions for a while to get the hang of it. These are questions that will ask “which of the following is the conclusion of the author” or “which of the following is the main point of the author’s statement.” Any student who tries to answer an assumption question – roughly 65% of all logical reasoning questions – before knowing the conclusion and evidence of the prompt is setting themselves up for difficulties.


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