Logical Reasoning

PT126 · S4 · Q25 A study of 86 patients, all

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A study of 86 patients, all of whom suffered from disease T and received the same standard medical treatment, divided the patients into 2 equal groups.

Conclusion (clearly)

Support group meetings do not help patients with disease T live longer.

Evidence

In a study of 86 patients with disease T, who all received the same standard medical treatment, one group attended weekly support group meetings, but no one from the other group did.

After 10 years, 41 patients from each group had died.

Evaluate

When we see causal arguments in Strengthen / Weaken (as we so commonly do), they usually start by presenting an Asymmetric Comparison, which we nickname "a curious fact". The author's conclusion states or assumes the causal story behind that difference.

But anti-causal arguments usually start with a Symmetric Comparison, which allows the author to claim, "See? This thing didn't make any difference". With anti-causal arguments, if we're going to defend the idea that thing X did make a difference, then we usually need to "make an excuse" for why two things appeared to be the same.

For example, if we wanted to defend the idea that Laura's LSAT book is better than Matt's LSAT book, but students who used Laura's book scored the same on their eventual test as did students who used Matt's book, we would need to "make an excuse" for why Laura's students (supposedly using the better book) ended up scoring similarly.

We can say, We show that Laura's students and Matt's students didn't start on an even playing field, so that we can argue that .

Goal

Here, we'd be thinking,

Given that .... 41 patients in each group died,

How can we argue that ... the support group meetings did help patients with disease T live longer than they would have without the support group meetings?

25.

Which one of the following statements, if true, most seriously weakens the argument?

Of the 4 patients who
Weaker Impact
This ain't nothing, but ain't much. It does help us argue that support group meetings are helping people live longer, but it only allows us to argue that when it comes to 4 of 86 data points. The correct answer applies to a wider swath of data points, so it has more impact.
7% picked this
For many diseases, attending weekly
No Impact
We can tell from the logic of this paragraph that disease T is not among the many diseases for which weekly support group meetings is part of the standard medical treatment. After all, all 86 patients received the standard medical treatment for disease T, but only 43 of them attended weekly support meetings.
1% picked this
Correct
The members of the group
Why this is right
This helps us argue that "support group meetings do help patients with disease T live longer". After all, on average, the 43 patients who attended weekly support group meetings lived 2 years longer than the 43 patients who didn't attend weekly support group meetings! That's pretty compelling evidence (much stronger than what we get from choice A). Even though an equal number of patients in each group died, that doesn't mean that support group meetings made no difference. Apparently they made an "extra 2 years of life" difference!
Skill tested: Weaken · how this choice captures the argument's function is the move to repeat next time.
90% picked this
Some physicians have argued that
No Impact
This is incredibly weak (some = at least one physician), and who cares whether it gives patients less faith in the standard treatment. We care about life span. Do the weekly support group meetings help them live longer? This answer doesn't address that concept.
1% picked this
Everyone in the group whose
No Impact: cope vs. survive
The conclusion wasn't saying that support group meetings were worthless for patients with disease T. If it had, then we could weaken it by saying, "Sure it might not help you live longer, but it improves your qualify of life while you're alive. It helps you better cope with the illness." However, the conclusion is purely about whether or not these support group meetings help patients live longer, so this answer isn't speaking to what we care about.
2% picked this

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