Q7 - Pollster: When opinion researchers need a population

[ohthatpatrick]

Question Type:
Necessary Assumption

Stimulus Breakdown:
Conclusion: If census were voluntary, national polls would be less accurate.
Evidence: If census were voluntary, participation rate would be lower. National polls base their "representative samples" on census data.

Answer Anticipation:
The missing link here is that "If participation rate were lower, then the demographic picture offered by a census would be less accurate".

Since this argument has such a flagrant missing link, I wouldn't worry about trying to think through potential objections and would just go the answers looking for something like "if fewer people participated, it would skew the demographic picture of the census".

Correct Answer:
C

Answer Choice Analysis:
(A) We don't care whether it's the only way or not the only way. We just care whether "fewer participants would affect the demographic accuracy"

(B) This also doesn't get at the crucial gap between "lower participation rate" in premise and "less accurate results" in the conclusion. We already have a premise baked-in that the participation rate will be lower. If we negated this answer, and it was saying that many previous non-participants will now participate, that sounds like the census sample WILL be different and thus potentially less accurate. So negating would only strengthen the conclusion.

(C) YES, this works. If we negate it, "the two groups would be IDENTICAL in termsof demographics", then we torch the argument. A lower participation rate wouldn't skew the demographic picture if every demographic reduced by a similar proportion. The author thinks that the group we'd get with a voluntary census would offer a different demographic picture for national polls to use.

(D) Out of scope. "The people who refuse to participate in opinion polls"? This argument never came close to dealing with them.

(E) The author doesn't need to assume that the participation rate stays essentially the same from census to census. No matter what type of participation fluctuation or trend the census has, the author's argument can still proceed, and we will still be left wondering whether "lower participation rate = less accurate results".

Takeaway/Pattern: This is a very classic term shift argument. There is a lot of filler to begin the paragraph, but the argument boils down to "If participation were voluntary, X would happen". Thus "if participation were voluntary, Y would happen". The assumption here is that "X leads to Y".

In the specific terms of this argument, it was that "lower participation rate leads to less accurate results". The results are only less accurate if they cease to reflect the same demographics. And (C) is getting at the idea that "if participation were voluntary, it would reflect different demographics".

#officialexplanation