Q4 - A survey published in a leading medical journal

[ohthatpatrick]

Question Type:
Flaw

Stimulus Breakdown:
Conclusion: Aerobic exercise greatly benefits people's health.
Evidence: Lots of surveys confirm the correlation between aerobic exercise and lower rates of lung disease.

Answer Anticipation:
Well, we only had to wait until Q4 before we got our first Causal Explanation of the test!

This is classic "Correlation vs. Causality": just because aerobic exercise and less lung disease are correlated doesn't let the author conclude that it MUST be the case that aerobic exercise CAUSES the less lung disease.

The most important reaction we have to causal conclusions is,
"Is there some OTHER WAY to interpret/explain the same evidence?"

How else could we explain why aerobic exercise and less lung disease are correlated?

We could use REVERSE CAUSALITY and say "people WITH lung disease are obviously going to have a hard time doing aerobic exercise, so maybe the correlation exists because LACKING lung disease causally allows someone to participate in aerobic exercise".

We could also use THIRD FACTOR and say "maybe wealth is the common cause of good health care leading to less lung disease and of having enough free time to do aerobic exercise".

Correct Answer:
C

Answer Choice Analysis:
(A) This would never be a flaw … trusting science over what-people-say.

(B) Not true. It said that "other surveys have confirmed these results".

(C) YES! This is correlation vs. causality.

(D) Extreme assumption. The author doesn't have to assume that ALL people without lung disease are in good health.

(E) This wouldn't be an objection. It sounds as though it strengthens, or at least aligns with, the author's conclusion.

Takeaway/Pattern: If the Correlation vs. Causality flaw doesn't already jump out at you, practice testing yourself on the common phrasings for CORRELATIONS. The better we get at hearing things like "the more X, the more Y", or "ppl who are X are more likely than those who aren't to be Y", the sooner our brains can light up to the awareness that LSAT is rolling out its most famous argument archetype.

#officialexplanation

[FaridR737]

Hmm. I do get why C is correct, however I was going back and forth between C & D due to the following reasons:

There isn't a direct equation to reduced lung disease = significant beneficial effect on people's health (i.e. there is a gap / assumption that has to be made). What if doing aerobic exercise did help with lung disease, but some other disease prevented better health and/or doing aerobic exercise exacerbated some other condition that made health worse overall, but lung disease better...

Such a case can make D sound like the proper flaw since D states "presumes, without providing justification, that anyone who does not have lung disease is in good health"...

or am I missing seeing some key word that makes D unworkable?

[A B]

Hey! So, not sure if this is 100% right but I think one key here that you might have missed is the difference between something having a beneficial effect on a person's health vs. someone being in good health overall. I think D is really unwarranted because something can have a beneficial effect on a person's health but they can still be in poor health. For example, someone could be obese and if they started exercising twice a day it could help decrease their risk of diabetes, however, they could still be at risk of high cholesterol and high blood pressure and heart disease, etc. and I wouldn't necessarily say then that that person was in good health. So, I'm not sure it's answering exactly the point you brought up, but I think it's another reason to knock out D that I don't think you mentioned.

In the end, I think the only thing it presumes maybe is that, if you don't have lung disease, your health has been improved, but remember that "improved" is a relative word and thus does not indicate that something is good. Just because Annie is taller than Jackie doesn't mean Annie is tall.

Let me know if I can expand on anything else here! (or if you thought any part of that was wrong - though I hope not!)

[ohthatpatrick]

I see the hesitation with (C), but when you read the conclusion, do you think the author is referring to a DIFFERENT benefit on people’s health?

If we say, “How should I know which benefit the author is referring to?”
LSAT will say, “Use common sense!”

The blurb that is written before every LR section says that we shouldn’t add ideas that are by commonsense standards implausible, superfluous, or incompatible with the passage.

For us to interpret the health benefit in the conclusion as referring to something other than the lowered risk of lung disease (the only aforementioned potential health benefit), we’d be adding some implausible/superfluous/incompatible idea that even though the author was talking about aerobic exercise in connection to lung disease, the health benefit being described in the conclusion has nothing to do with lung disease.

And the previous poster crushed it in describing (D).

I’ll just add, remember that “presumes = assumes”.
If you had read this argument and were asked a Necessary Assumption question stem, would you be comfortable saying that in this paragraph, the author clearly assumed that “every single person in the world without lung disease has good health”?

If you wouldn’t pick that as a Necessary Assumption answer, then you can’t pick (D). If you would pick it on a Necessary Assumption question, then you should pick (D).

That’s how “presume / takes for granted” answers work.