In the interest of helping the community, I will offer my thoughts on the question. Tracing these lines of logic led me to the correct answer in 2:08.
Quote:
In a ten-year study, one group of volunteers was given a medical screening for disease X every year, whereas an otherwise similar group of the same size was only screened for disease X at the end of the study. Nine percent of the first group were diagnosed with disease X during the study and received treatment, but only six percent of the second group were diagnosed with disease X when they received the screening at the end of the study. The researchers concluded that during the ten-year period, disease X must have disappeared without medical treatment in some individuals in the second group.
In order to evaluate the strength of the researcher's reasoning, it would be most helpful to know which of the following?
In any evaluation CR question, the goal is to find an answer choice that creates a meaningful two-way conditional:
1) if Yes, then the argument or conclusion is affected in a significant way
2) if No, then the argument or conclusion is affected in a significant way
Note that it is
not the goal to prove anything, or to create one meaningful conditional while ignoring the other. That said, we can break down the passage:
- The opening line introduces a ten-year study and informs us on two groups in that study, one tested for a certain disease every year, the other at the end of ten years.
- The second line of the passage provides findings relating to each group: nine percent of the group screened annually were diagnosed with the disease, while six percent of the other group were diagnosed with the disease after a decade.
- The conclusion appears to be drawn on a percent-to-percent comparison of the two groups, since the researchers concluded that during the ten-year period... some individuals in the second group, which we can call the 6 percent group, must have had the disease but—without medical treatment—were no longer found to have it by the end. That is, the disease apparently disappeared on its own at some point during the decade.
I would not bother pre-thinking anything, but would jump straight into the answer choices with a firm grasp of just what the passage outlines and on what basis the conclusion is drawn.
Quote:
A. Whether there were statistically significant lifestyle differences between the individuals who were diagnosed with disease X and those who were not
I would start by pointing out that we have no idea what to make of
statistically significant. A mathematician friend of mine once busted me on this point when I had written a question that used such terminology. Researchers can set statistical significance at just about any level they choose, and track any variable they choose. Think about it: perhaps a 0.01 percent (1 in 10,000) incidence of a trait increases to 0.015 percent, representing a
fifty percent increase—something that sounds significant—yet the overall incidence remains well below even 1 percent. (Medical research uses this sleight of hand all the time, and irresponsible writers often spin sensationalist arguments without shedding light on the actual findings or figures.) In this case, what are
statistically significant lifestyle differences? The difference between smoking and not smoking, or between the person who eats more than 6 servings of fruits and vegetables a day and one who eats 5? The term loses meaning once we stop and think about it.
The easier target lies at the end of the answer choice. The
individuals not diagnosed with the disease represent over 90 percent of the participants from each group. We are not examining the missing 3 percent between the 9 percent group and the 6 percent group. This consideration would not help to evaluate the argument.
Quote:
B. How many people volunteered for the study because they knew that they had an especially high risk for disease X
It is hard to see how anything after
because could make this consideration the one we need to evaluate the argument. Whether people
volunteered for one reason or another, the results of the study would remain unchanged, and we would be no closer to gaining any insight into the difference between the groups.
Quote:
C. How long it takes to be treated for disease X
You might argue that if the disease takes a few years to be treated, then the extra 3 percent in the 9 percent group might not have had time for the disease to be eradicated, hinging on another
if—if many of those diagnosed with the disease were found to have developed it more recently in the ten-year period. However, that still would not help explain why members of the other group, those who were
untreated until the end of the ten-year period, did not develop the disease in like numbers. Focusing on the treatment period is a blind alley.
Quote:
D. Whether volunteers were told what disease they were being screened for
Even if you believe in psychosomatic relationships such that merely
thinking about cancer could switch its development on or off, the fact remains that regardless of how you answer this question, yes or no, we would be no closer to teasing apart the members of the two groups. Presumably, they would all have been informed equally.
Quote:
E. How frequently on average the medical screening used in the study produces erroneous diagnoses of disease X
Now this is of interest. Remember, we have one group whose members are screened every year for a decade, and another group whose members get a single screening. You do not have to be a math guru to see that the balance is tilted 10:1. If we know this frequency, we can calibrate the results and make a more informed evaluation of the researchers' conclusion; if we do not, then the question remains why one group without any treatment seemed to come out ahead of the other group. This is a pertinent concern either way we look at it, and we have found our answer.
I would be remiss if I did not add that on more difficult questions, you are less likely to encounter easily discernible answer patterns. That is, I would
not recommend memorizing this question and the correct answer choice in hopes of applying the same logic to the next evaluation question. The chain of logic and the contextual information are what matter. It is more important to establish a sound method by which to tackle such questions.
Good luck with your studies.
- Andrew
close
02 Aug 2023, 04:00
44%
(02:15)
wrong 
