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Complete Question Explanation

Evaluate the Argument—CE. The correct answer choice is (C)

In the recent study discussed by the journalist in this stimulus, people who drink three cups of decaffeinated coffee per day were compared with people who drink three cups of regular, caffeinated coffee per day. The group of decaffeinated coffee drinkers were twice as likely to develop arthritis (inflamed joints that result from damaged connective tissue). The author concludes that decaffeinated coffee must contain ingredients that can damage connective tissue and cause arthritis:
  • Premise: ..... Regular consumers of decaf coffee were found to be twice as likely to develop arthritis, a condition ..... ..... ..... resulting from damaged connective tissue.

    Conclusion: ..... Decaffeinated coffee must have ingredients that cause damaged connective tissue.
Based on a correlation, the author has drawn a causal conclusion. The stimulus is followed by an Evaluate the Argument question, so the correct answer choice will provide an inquiry relevant to the issue of whether decaffeinated coffee is really the culprit.

Answer choice (A): This choice attempts to introduce another consideration—regular exercise—but the question of whether regular exercisers drink decaf is not relevant to this study, which assessed two groups with very specific drinking habits: exactly three cups of either regular or decaffeinated coffee, depending on the group. The tendencies of regular exercisers is not relevant to the argument made by the journalist, which is limited to the comparison of two specific groups, so this choice should be ruled out of contention for this Evaluate the Argument question.

Answer choice (B): This choice deals with how often decaffeinated coffee drinkers tend to drink coffee, as compared with regular coffee drinkers. These tendencies, however, are not relevant to the journalist’s argument, which is focused on people who drink a very specific amount of their chosen coffee. Since the study discussed dealt exclusively with people who drink exactly three cups of coffee per day (be it caffeinated or decaffeinated), this answer choice would not be helpful in evaluating the journalist’s argument.

Answer choice (C): This is the correct answer choice. The question of whether caffeine can slow the degeneration that causes arthritis is certainly a relevant one; if caffeine is able to slow degeneration, then that would provide another possible explanation of the survey’s results: the author concludes that the decaf drinkers were consuming something that was detrimental, but perhaps in reality, the regular coffee drinkers were giving themselves an extra advantage.

Answer choice (D): The study discussed by the journalist deals only with people who drink three cups of coffee per day, so the issue of whether most coffee drinkers consume more is irrelevant. Since this choice is not helpful in evaluating the journalist’s argument, it should be ruled out of contention for this Evaluate question.

Answer choice (E): Whether the arthritic are very likely, or exceedingly unlikely, to consume coffee does not matter in this case, since the study in the stimulus focuses on the differences between people who drink three cups of regular coffee per day, and those who drink three cups of decaffeinated coffee per day. Since the issue presented in this choice is irrelevant to the journalist’s argument, it cannot be the right answer to this Evaluate question.
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Could you please explain why c is the correct answer? The journalist is claiming that there is something in decaffeinated coffee causing connective tissue damage, and this substance is not in caffeinated coffee. If the answer to C is yes, degeneration of connective tissue is slowed by consumption of caffeine and other stimulants, that would prove or disprove whether this damage causing element is in the decaffeinated coffee. Also, I don't see how answering no, it does not effected the degeneration of connective tissue, would affect the argument either.

Thank you.
 Ron Gore
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Hi there,

The argument is flawed because the journalist takes a correlation between decaffeinated coffee and arthritis and concludes from that evidence that something in decaffeinated coffee exacerbates arthritis. That conclusion is flawed, like any conclusion that infers causation from correlation.

In this Evaluate the Argument question, the correct answer choice will help us assess the validity of the conclusion. The argument's causal flaw is the most likely place for the correct answer choice to focus. Answer choice (C) focuses on that causal relationship. If arthritis is slowed by caffeine, then it may not be the case that something in decaffeinated coffee worsens arthritis. Rather, it may be that the presence of caffeine slows it. People who don't drink decaffeinated coffee would be lacking what slows arthritis, and so their arthritis, if they were susceptible to suffering from it, would be worse.

So, answer choice (C) is correct because it relates to the causal weakness in the stimulus and explores the possibility that there was a different causal relationship at play between caffeine and arthritis than the journalist assumed to be the case.

Hope that helps.

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Can I say that A is wrong b/c it does not address the relationship mentioned in the conclusion which is what the question stem is asking us to do?
And that even if people who exercise are more "likely" or even "always" drink decaf beverages, ie decaf coffee, (I don't think just b/c beverages is not the same as coffee is a good enough reason to make this answer wrong), the conclusion could still be true, so that doesn't help us evaluate it. The opposite, if they are not likely, or even "never" drink decaf, it does not make the conclusion anymore true?

And if this was a weaken causal flaw question, would this answer be right b/c it does talk about a possible 3rd factor that could cause the damages to the connective tissue?

 Adam Tyson
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I think you are on the right path, PeterC. Answer A doesn't really give us much ammo with which to evaluate the argument we were asked to evaluate. If people who exercise are more likely to drink decaf stuff, what does that do to the argument? We might want to say it weakens the argument by introducing a possible alternate cause, but since it merely sets up a correlation and not a possible alternate cause, it's pretty weak. What if they are not more likely to do so? That might be tempting to consider that it eliminates a possible alternate cause, but again it's pretty weak. For these reasons I think A, as written, still wouldn't be a great causal-weaken answer. That is, if it said that those that exercise ARE more likely to drink decaf, it still might not be enough to tell us that exercise is a possible alternate cause for arthritis because we don't know that the people studied were broken into exercise and non-exercise groups, or whether that tendency is consistent when we look at those who drink three or more cups of coffee specifically.

Answer C, though, gets right to it. If caffeine HELPS, then the argument is pretty well destroyed by an alternate cause for the correlation, and if caffeine does NOT help, then the argument is helped nicely because that alternate cause is eliminated. Boom!

Good analysis - keep up the good work!
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I found the explanation for answer choice (A) a bit unsatisfactory, since it basically dismissed the idea of regular exercise as irrelevant. I do admit that decaffeinated "beverages" is a red flag, but I would like to discuss whether changing that into decaffeinated "coffee" would make any difference to how you would assess this answer choice.

My understanding of the situation: if the answer to this question is "yes, people who exercise regularly are indeed more likely to drink decaffeinated coffee than those who do not", then the journalist's argument is weakened, since an alternative cause to developing arthritis--exercise, is proposed. On the other hand, if the answer to this question is "no, people who exercise regularly are no more likely to drink decaffeinated coffee than those who do not", then the journalist's argument is strengthened, since an alternative case is eliminated. A question with this "if yes then weaken, if no then strengthen" quality is a good answer choice for an Evaluate question.

Please let me know if I am mistaken in thinking that the "beverages" vs "coffee" difference is the only thing that makes answer choice (A) wrong. Thank you very much!
 Adam Tyson
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The problem with that analysis, and with answer choice A, nutcracker, is that it completely ignores the folks that drink regular coffee. Let's say that people who exercise are more likely to drink decaf than people who don't exercise. What does that tell us about whether people who exercise are also more or less likely to drink regular coffee? This answer doesn't contribute to a correlation between exercise and arthritis, because we don't know about the corresponding figures for regular coffee drinkers. Try these stats on for size:

10% of all people who do not exercise drink decaf
10% of all people who do not exercise drink regular coffee
80% of all people who do not exercise drink no coffee at all
30% of all people who exercise drink decaf
70% of all people who exercise regular coffee

Now, with these numbers, is exercise a possible alternate cause for arthritis instead of decaf? I don't think so, because then we should expect a higher incidence of arthritis among the regular coffee drinkers!

Because answer A ignore the other group of coffee drinkers, we can't treat exercise as an alternate cause. It would be much better if it said something like "People who drink decaf are more likely to exercise than people who drink regular coffee". That would suggest that among the two groups there is another factor that correlates with higher arthritis figures, and which could therefore be an alternate cause. A just doesn't do that for us.

This stimulus sets up a pretty classic causal problem, and we've seen many like it (including at least one other that comes to mind that also involved coffee, that time with having an impact on our immune systems). Two groups that do two different things have different results, one doing worse than the other. We blame the thing that one group does for making things worse, and overlook the possibility that what they did may have had no effect while the thing the other group did made things better, or vice versa.

I hope that causes you to think alternatively about answer A, and to see what makes it worse (or makes answer C better)!
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I understand all the explanations and am starting to see that C is a much better answer than A. However, I wanted to flush out my reasoning process for rejecting C in favour of A when I did this question. I thought that even if C is true - that caffeine slows the degeneration of connective tissue - the conclusion could still be true. It could totally be possible that both decaf coffee damages connective tissue and regular coffee slows its degeneration. Because of this I rejected C, thinking that it doesn't invalidate the conclusion as it merely calls it into question. But was what I did wrong because this isn't a "weaken" question but an "evaluate the argument" question? So even if C doesn't invalidate the conclusion, it is still the most useful & relevant piece of info that allows the reader to evaluate the question?

Thanks very much.
 Brook Miscoski
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You are correct that this is an "evaluate" question rather than a "weaken" question. What you should ask yourself about (C) is this--does changing the answer to the question that (C) asks change how I view the argument?

(C) asks whether caffeine slows the degeneration of connective tissue. If the answer is "yes," then the argument seems weaker, because the explanation for better connective tissue in people who drink caffeine could be the caffeine. If the answer is "no," then the argument seems stronger, because we have eliminated a competing explanation for the observed difference between people who consume caffeinated coffee and people who consume caffeine decaffeinated coffee. The fact that the argument is weaker or stronger depending on how you answer (C) shows that (C) is helping to evaluate the argument.

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