In response to office workers' worries about the health risks

Question

In response to office workers' worries about the health risks associated with using video display terminals (VDTs), researchers asked office workers to estimate both the amount of time they had spent using VDTs and how often they had suffered headaches over the previous year. According to the survey, frequent VDT users suffered from headaches more often than other office workers did, leading researchers to conclude that VDTs cause headaches.

Which one of the following, if true, most undermines the researchers' conclusion?

(A) Few of the office workers surveyed participated in regular health programs during the year in question.

(B) In their study the researchers failed to ask the workers to distinguish between severe migraine headaches and mild headaches.

(C) Previous studies have shown that the glare from VDT screens causes some users to suffer eyestrain.

(D) Office workers who experienced frequent headaches were more likely than other workers to overestimate how much time they spent using VDTs.

(E) Office workers who regularly used VDTs experienced the same amount of .iob-related stress as workers who did not use VDTs

Fabiocafarelli · Answer

Conclusion: VDTs cause headaches.
Evidence: Frequent VDT users suffered from headaches more often than other office workers did.
Relevant factor influencing evidence: the time spent using VDTs is based on an ESTIMATION. So is the frequency of the occurrence of headaches.

Option A. Who are the FEW office workers in question? Are they those who suffered headaches, or those who did not? It would be helpful to know this. Furthermore, does the participation in a health program - regular or otherwise - ensure that one will not have headaches - and even if it did, what would be the connection between that and the effects of using VDTs regularly? IRRELEVANT.

Option B. The distinction between mild and severe headaches narrows the scope of the passage and so makes this option irrelevant. The passage is talking about headaches in general, and this general category encompasses all possible degrees of severity. IRRELEVANT.

Option C. The passage draws a conclusion on the basis of a particular survey: therefore, the weakening or strengthening of that conclusion must occur within the framework of factors relevant to the survey. What previous studies have shown is therefore beside the point. Furthermore, the conclusion that we are asked to weaken involves headaches: eyestrain has nothing to do with it. IRRELEVANT.

Option D. We need to take note of the fact the evidence used in the researchers' survey is vitiated (as is the conclusion) by the fact that it is based on ESTIMATIONS. These do not readily provide solid fact: they can very easily be highly subjective and wildly inaccurate. If, as this option states, the workers who experienced frequent headaches were more likely than other workers to overestimate how much time they spent using VDTs, the conclusion that VDTs cause headaches is greatly weakened. The reason for this is that if the time spent in front of VDTs by headache-sufferers is significantly less than it is estimated to be, there is significantly less evidence that VDTs cause headaches. CORRECT.

Note also that this is the only option that refers - in the word OVERESTIMATE - to the factor that vitiates the evidence and the conclusion of the argument, and is therefore a prime contender for the position of correct answer. If you were in real doubt between a number of options, this factor could help you to make an intelligent guess.

Option E. If the evidence and conclusion of the argument involved the claim that VDTs have an impact on health in general, it would be possible to state (assuming that JOB-RELATED STRESS falls under the category of HEALTH) that this option weakens the argument. The option would indicate that since this kind of stress occurs just as frequently among VDT users as among those who do not use them, VDTs are not its cause. Nevertheless, the conclusion of the passage is that VDTs cause headaches, and the evidence on which this conclusion rests is that frequent VDT users suffered headaches more frequently. We therefore have to stick with headaches. MISLEADING AND IRRELEVANT.

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HKD1710 · Answer

VDT causes headaches

to weaken this relationship any choice that says study data is wrong then this conclusion will not hold. choice D says exactly that.

Mkrishnabdrr · Answer

In response to office workers' worries about the health risks associated with using video display terminals (VDTs), researchers asked office workers to estimate both the amount of time they had spent using VDTs and how often they had suffered headaches over the previous year. According to the survey, frequent VDT users suffered from headaches more often than other office workers did, leading researchers to conclude that VDTs cause headaches.

Which one of the following, if true, most undermines the researchers' conclusion?
(A) Few of the office workers surveyed participated in regular health programs during the year in question.
(B) In their study the researchers failed to ask the workers to distinguish between severe migraine headaches and mild headaches. 
(C) Previous studies have shown that the glare from VDT screens causes some users to suffer eyestrain. 
(D) Office workers who experienced frequent headaches were more likely than other workers to overestimate how much time they spent using VDTs.
(E) Office workers who regularly used VDTs experienced the same amount of job-related stress as workers who did not use VDTs.

Source: LSAT CR

prachi18oct · Answer

AB are out of scope
E strengthens by ruling out other reason
Between C & D 
C talks about eyestrain that can be a cause of headache but it uses some. Some can be from 1 to all . So doesn't weakens much
I go with D.
If office workers who have frequent headaches spend much less time than they estimate ..VDT might not be the cause at all

arif24 · Answer

Ans - D 
Because it seriously undermines by stating that the workers didn't estimate the actual time they had spent using VDTs which leads researchers to conclude wrong about headache

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sallysea · Answer

Merged topics. Please, search before posting questions!

parampreet1997 · Answer

In CR, can we question the validity of the facts?
Isn't D option questioning the validity of the fact?

MartyMurray · Answer

Interesting question, and understanding the answer to your question can be key for getting certain types of CR questions correct.

Here's what's going on.

Sometimes, the evidence supporting a conclusion in a CR question is what "records indicate," what "people have reported," or something else that involves reporting, perceptions, or observations. In such a case, the fact stated in the passage is not  what has been reported . The fact stated in the passage is  that something has been reported .

So, in such cases, what has been reported may not be true. All we know for sure is that it has been reported.

Accordingly, in this case, "frequent VDT users suffered from headaches more often than other office workers did," is not a fact stated by the passage. Rather, that information is based on survey results that involve estimates. So, the only solid fact we have is that office workers estimated "both the amount of time they had spent using VDTs and how often they had suffered headaches over the previous year."

The correct answer does not dispute that fact. What it calls into question is the estimates, which are not facts.

Thus, the correct answer weakens the argument by showing that, even though it is factual that people estimated "the amount of time they had spent using VDTs and how often they had suffered headaches" and that "according to the survey, frequent VDT users suffered from headaches more often than other office workers did," the conclusion may not be correct because the estimates are likely off.

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In response to office workers' worries about the health risks

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