Q11 - Last year the Lalolah River was ranked by

[ohthatpatrick]

Question Type:
Flaw

Stimulus Breakdown:
Conclusion: Clean up measures must be working.
Evidence: Last year, LR was ranked as the most polluted of the 15 local rivers. This year, it's ranked 3rd worst.

Answer Anticipation:
This is the most classic argument template:
PREMISE = curious fact / correlation / change
CONCLUSION = explanation for / interpretation of that premise.

Here, we've got
CURIOUS CHANGE: "LR went from most polluted to 3rd most polluted".
AUTHOR'S INTERPRETATION: "The measures taken to clean up the river must have IMPROVED the river from 1st worst to 3rd worst."

We always address this classic template with the same two questions.
1. Is there some OTHER WAY to explain the Curious Fact?
Why else could it be that LR went from worst to 3rd worst? maybe "2 rivers ranked below it last year got way more polluted"
2. How PLAUSIBLE is the Author's Explanation?
Do we know whether they actually did anything? what evidence is there that actions were helping? in areas where measures WEREN'T taken, is the river still just as polluted?

On a Strengthen/Weaken question, we'd have to worry about both types of answers. On Flaw/Nec Assump, they are almost always just testing the #1 ideas.

Correct Answer:
E

Answer Choice Analysis:
(A) Famous Flaw: UNPROVEN vs. UNTRUE. But that's not what was happening here. The author just assumed ONE possible cause must be the cause.

(B) Famous Flaw: EQUIVOCATION. But that's not happening here. We use "most polluted" in the same sense both times.

(C) The BASIS for the ranking doesn't quite matter. We're just saying the author is too sure about one possible reason the ranking changed.

(D) Famous Flaw: PART vs. WHOLE. But that's not happening here. We're just saying that the author assumes that LR was improved by clean-up measures, but maybe its ranking rose for a different reason.

(E) YES!, but tough answer choice language. The most obvious objection to this argument is that the ranking didn't change because LR improved, it changed because 2 rivers formerly below it got worse. That's what (E) is getting at. The evidence is about a decrease relative to other ranked rivers "LR went from worst to 3rd worst". The conclusion is about an absolute decrease "Measures to clean up the river must be working (i.e. the river must be less polluted than it was before)". This answer choice accurately describes the mismatch between the Premise and the Conclusion, and it conveys the idea that the author has failed to consider that a move from worst to 3rd worst could be explained by a relative change or an absolute change (or both).

Takeaway/Pattern: The difficulty here comes only from the wording of (E). Experienced students should instantly recognize the causal argument template and react primarily by thinking, "how ELSE could we explain the same background fact"? And experienced students should know the famous flaws referred to in A, C, D, making those quick eliminations.

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