Q17 - Expert witness: Ten times

[LSAT-Chang]

I chose (C) for this but only because the rest 4 were not tempting answers at all. The problem I had with (C) was that it was still "less" than 9.5 -- so the conclusion still holds. Doesn't it?

So the core I had was:

in all ten cases, a single drop of the defendant's blood stain was much less than 9.5cm, and always between 4.5~4.8cm

therefore

a single drop of the defendant's blood stains much less than 9.5cm of the fabric

Is (C) a minor weakener since the conclusion is based on the evidence that in all ten times, it stained in between 4.5~4.8 and concluded from this that it stains "much less" than 9.5, but if in the 11th test drop, it stained 9.3cm, then it isn't really "much less" as the conclusion states? Does my question make sense?

[timmydoeslsat]

Question makes perfect sense.

You must realize that this argument is a pretty good argument. Really the only assumption you can find to undermine this is that 10 drops is a good indicator of matching it to this 9.5 cm stain fabric.

And, like clockwork, the LSAT goes after this idea of 10 not necessarily encompassing something that can derive a conclusion.

The conclusion is that a single drop stains much less.

And having a situation where the first ten times were around 4.5 - 4.8 cm, and this 11th one being 9.3...it really weakens any kind of conclusion we could make. For all we know, that 12th drop could be 9.9, etc. It shows that we cannot make a conclusion of "much less."

[jason.tarre]

Is (B) wrong because you have to make an assumption that the expert witness can fudge the data enough to undermine the conclusion? Or is it wrong because the answer choice doesn't explicitly mention the size of the blood stain? Or something else?

Thanks!

[timmydoeslsat]

Is (B) wrong because you have to make an assumption that the expert witness can fudge the data enough to undermine the conclusion? Or is it wrong because the answer choice doesn't explicitly mention the size of the blood stain? Or something else?

Thanks!

I think it is wrong because we do not know how this evidence ties into the prosecution's case. Perhaps this expert witness is telling us evidence that would hurt the prosecution's case.

Also, answer choices like that with "sometimes" is not a very good weakener. We don't know if it is going on in this particular case, and sometimes could imply one time out of 250,000.

[gplaya123]

What about D though?
Wouldn't this weaken as well, where this shows the possibility that the area of stain could be over 9.5?

[jonathanthegrey]

I considered (C) to be completely wrong when looking through the answers. I'm still not totally sure about it.

"Much less" seems like a completely arbitrary standard. Is 9.3 cm^2 still much less than 9.5 cm^2, despite being greater than 4.5-4.8? I don't mean to seem like a stubborn relativist (or the annoying guy who wouldn't stop raising his hand during philosophy lecture), but I don't think the conclusion of "much less" is undermined just because the gap has narrowed; the label can still remain.

Thanks.

[bp0]

Wait,

Why is B wrong here? Can someone elucidate me on this? If expert witnesses have sometimes been known to fudge data, that is enough to undermine the conclusion. Whether it is for or against the prosecution is irrelevant. If the data MIGHT be fudged, then that leaves us with pretty large skepticism to the conclusion.

I mean, If I told you to invest in, let's say Wells Fargo, because I think it is a good company based on the Financial Statistics. Then, I give you the companies balance sheet and I tell you, well, all the data might be fudged. Would that not undermine my conclusion that it is a good company based on Financial Statistics?

I would argue so. Anyone want to counter my argument?

Also the fact that the 11th test drop is 9.3 cm^2 doesn't actually undermine the value of the evidence. What is MUCH LESS? 9.3 cm^2, in this incidence could be considered much less , that answer is simply subjective and depending on the context of the discussion. For example, let's say some guy comes up to you and says 900 dollars is much less than 1,000 dollars. To Warren Buffett, it doesn't seem like much less. He doesn't care. To a man who has children to feed and who's disposable income is 10 dollars less than 900 dollars, 900 dollars seems MUCH less than 1,000 dollars.

Anyone want to take a go at this

[WaltGrace1983]

Wait,

Why is B wrong here? Can someone elucidate me on this? If expert witnesses have sometimes been known to fudge data, that is enough to undermine the conclusion. Whether it is for or against the prosecution is irrelevant. If the data MIGHT be fudged, then that leaves us with pretty large skepticism to the conclusion.

I mean, If I told you to invest in, let's say Wells Fargo, because I think it is a good company based on the Financial Statistics. Then, I give you the companies balance sheet and I tell you, well, all the data might be fudged. Would that not undermine my conclusion that it is a good company based on Financial Statistics?

Your right, it is enough to slightly undermine the conclusion. However, we are looking for the one that MOST undermines the conclusion and in this case, as with the cases of pretty much all strengthen/weaken questions, the more specific the better. We are talking strictly about this expert witness. How do we know that this expert witness would be within the group that "sometimes" fudges data.

Oddly enough though, if the answer choice would have said something like "Expert witnesses typically fudge their data..." that would posit a degree of certainty that (B), as it is, simply doesn't.

As a general rule of thumb, if an answer speaks to a majority then it is a fairly good strengthener/weakener. If it doesn't, there may be a better answer.

Also the fact that the 11th test drop is 9.3 cm^2 doesn't actually undermine the value of the evidence. What is MUCH LESS? 9.3 cm^2, in this incidence could be considered much less , that answer is simply subjective and depending on the context of the discussion. For example, let's say some guy comes up to you and says 900 dollars is much less than 1,000 dollars. To Warren Buffett, it doesn't seem like much less. He doesn't care. To a man who has children to feed and who's disposable income is 10 dollars less than 900 dollars, 900 dollars seems MUCH less than 1,000 dollars.

Anyone want to take a go at this

Much less is kind of a sticky term here, I agree with you. However, what (C) does is actually undermining the evidence. Why? Because it shows that the evidence might not be complete. Isn't it strange that on the eleventh try the evidence was almost COMPLETELY different? This certainly undermines the evidence that 10 was sufficient because the 11th was so drastically different. Now the 11th might have been a fluke, but it still causes us to dismiss the validity of the evidence as sufficient.

[mjacob0511]

In all ten controlled circumstances, a drop of the defendants blood stained between 4.5 and 4.8 - much less than the expected 9.5. Conclusion: a single drop of the defendants blood (always) stains much less than 9.5.

The question asks us to undermine the "value" of the evidence. Well we know that it was done ten times, but maybe there are other factors. Maybe ten isn't representative and the area that gets stained could vary much more depending on the thickness of the blood that day or some other factor. Maybe for an hour after you drink soda, your blood remains more cohesive and will stain less of an area and after that it shoots back up to 15. Another possibility is that something about the fabric or the environment which it's in could affect the spill. The point is that we don't know that the ten 4.5-4.8s are representative and conclusive.

(A) Ok, so it would be more conclusive if the results would have been between 4.5-4.8 one hundred times? That doesn't mean it's not conclusive now. And if it happened a million times it would be stronger than one hundred times etc... there's no end to this argument because with more confirmed test results things can always be "stronger". Point is, the defendants blood still stains much less than 9.5 no matter how many times you prove it. It doesn't undermine the value of this evidence it just adds on.
(B) It seems to me that the expert witness is actually going against the prosecutor. We don't have all the information but the witness seems to be saying, "hey it couldn't be the defendant, because the stain area and amount doesn't match his blood type". Either way it's a pretty weak answer. So one dirty guy gets paid off by the prosecutor, so every time any witness testifies we will say "wait, he might have been paid off, the evidence is weak".
(C) Perfect. So ten times it was 4.5-4.8, but the eleventh time it was 9.3. Well if that's the case, it weakens the conclusion that the defendant's blood stains much less than 9.5, because here it was 9.3. It also clearly shows that the ten were not necessarily representative. Maybe the 15th was 4.2 and the 16th back up to 10.2. Strong weakener.
(D) Another person? They are trying to trick you into thinking that if another person's blood stains more than 9.5 than maybe the defendant's also could, but the point is that experiments were done with the DEFENDANT'S blood and his was shown to not stain more than 4.8, so we don't care about other people's blood.
(E) We don't even know what authority he claims to be. His testimony is simply regarding the defendants stain area and it's based on controlled experiments.

[jahid.mowla]

Would it be safe to say that choice B weakens the argument a little but C almost destroys the argument

The way my thinking revolved around this question is:

Expert witnesses sometimes fudge their data... weakens the argument by indicating some experts compromise the data, establishing this likelihood to show possibility of this pattern being done again in this specific situation but this does not guarantee or even come close to most experts doing this and even if most experts did this, the expert in this situation need not be those who do. Also the question asks which answer undermines the evidence most, whereas this choice undermines the interpreter of the evidence, not the evidence itself (which is why although most people would knock out B, I kept because I thought manipulation of data was at best, relevant)

However, B does not weaken the answer choice as much as C, which SUBSTANTIALLY weakens the argument's evidence, by directly attacking the evidence to show a much wider range of change in the 11th test and showing that the data acquired cannot be depended on for categorical judgement.

How would you judge my thinking process?

[ohthatpatrick]

Your thinking sounds spot on!

The one other thing you could add to hatin' on (B) is that THIS expert witness is actually according with the DEFENDANT's case, not the prosecutor's.

[contropositive]

I eliminated B and E right away because it just didn't seem relevant to the argument. Right?

Also, I think one way to get to the right answer is notice that the question stem is asking to undermine "value of the evidence"

[ohthatpatrick]

(B) and (E) aren't totally irrelevant, but they certainly don't feel like normal LSAT answers. I mean, this speaker IS an expert witness, so facts about expert witnesses must be SOMEWHAT relevant.

But both of them are super weak statements that say that "at least one" expert witness has fudged data and "at least one" expert witness was not really an expert. That's not grounds for much skepticism.

As you noticed, the question doesn't say weaken THE ARGUMENT / REASONING, it actually says to weaken the evidence. So since the evidence is about the blood stain measurements, we'd definitely be expecting something more directly on that subject.

Technically, (B) and (E) are still related to the evidence, though.
"fudging data" = distorting the evidence
"not an expert" = might be unintentionally botching the evidence

Those answers are just so weakly worded that there's almost no effect at all by saying them.

[ellylb]

Wait,

Why is B wrong here? Can someone elucidate me on this? If expert witnesses have sometimes been known to fudge data, that is enough to undermine the conclusion. Whether it is for or against the prosecution is irrelevant. If the data MIGHT be fudged, then that leaves us with pretty large skepticism to the conclusion.

I mean, If I told you to invest in, let's say Wells Fargo, because I think it is a good company based on the Financial Statistics. Then, I give you the companies balance sheet and I tell you, well, all the data might be fudged. Would that not undermine my conclusion that it is a good company based on Financial Statistics?

I would argue so. Anyone want to counter my argument?

I think this is something that you just have to accept in GENERAL with LSAT logic. If the LSAT presents you with an argument and asks you to weaken it, and an answer choice says something a long the lines of...."it isn't necessarily always the case" (eg. witnesses may have fudged the data) in the LSAT world that will not be the correct answer, because just because in some instance it might be the case, it isn't in ALL instances and thus it is not sufficient to CONCLUSIVELY, unequivocally and categorically weaken the argument. It might not be the case, then again.. it might be. That places a contingency on the weakening of the argument and that is not what the LSAT is looking for. The LSAT is always looking for an unequivocally damaging and undermining answer, no matter how weak or strong. If you understand this... you will no longer be fooled by the LSAT weakener - contingency trap. Something that SOMETIMES weakens the argument.. but not in each and every instance... will not be the correct answer.

[NitanS934]

I chose (C) for this but only because the rest 4 were not tempting answers at all. The problem I had with (C) was that it was still "less" than 9.5 -- so the conclusion still holds. Doesn't it?

So the core I had was:

in all ten cases, a single drop of the defendant's blood stain was much less than 9.5cm, and always between 4.5~4.8cm

therefore

a single drop of the defendant's blood stains much less than 9.5cm of the fabric

Is (C) a minor weakener since the conclusion is based on the evidence that in all ten times, it stained in between 4.5~4.8 and concluded from this that it stains "much less" than 9.5, but if in the 11th test drop, it stained 9.3cm, then it isn't really "much less" as the conclusion states? Does my question make sense?

A weaken question doesn't necessarily lead to a situation where the conclusion will no longer hold. It just means that the conclusion is less likely given that answer choice. And yes, you're spot on with your question. I agree with you that it's a minor weakener because "much less" is relative and doesn't tell us really anything. What if the author considers a difference of 0.2cm to still be "much less" than 9.5? The conclusion would in that circumstance still not be terribly weakened. But - a good part of LSAT strategy is to know when to pick an answer that you don't absolutely love because all the other answer choices are flat out wrong.