Q16 - Salmonella is a food-borne microorganism

[schmid215]

Had it down to A and B, but went with A. I don't see how detection at low-levels weakens the notion that the new test should replace the old test. Perhaps if we weren't comparing it with another defective test, and the conclusion strictly concerned the value of the new test, (B) would weaken, but we're only concerned with whether or not to replace the old test. Would we seriously be more likely to keep a test that can potentially miss certain strains of Salmonella instead of replacing it with another test that identifies those strains, just because the latter test detects at very low-levels? And it seems plausible that toxicity levels would be known anyway. I did not like (A) at all, but it seemed like it was the better answer, since what it says suggests, if very slightly, that the bacteria would also cause some kind of illness.

[a3friedm]

Hi there,

since this is a weaken question our answer choice is probably going to capitalize on the gap in logic between the premises and the conclusion.

Notice that in the stimulus, the first two sentences are just completely filler. It seems pointless to acknowledge, but when you see LSAC kind of throwing random information at you, you can expect they're going to try and trick you with a couple answer choices related to it.

the actual argument is
P1: Conventional tests slow & can miss strains
P2: New test can identify the presence or absence (this distinction is important) of material in all salmonella

C: Public Officials would be well advised to use the new salmonella test


Answer choice (B) gives us exactly what we need. Imagine if every food had some strand of salmonella and some of these strands are either harmless or not in a large enough quantities to have a harmful effect. All we know is it tests the presence or absence, so if that was the case this test would be useless.

(A) This doesn't do anything for our argument. All we care about is salmonella

(C) out of scope, we only care about salmonella.

(D) out of scope

(E)way out of scope

Notice how (C) and (E) come from filler language that didn't do anything for our argument? By recognizing that from the outset allows us to eliminate them really quickly. Also, (A) and (E) have the word "only" which whenever I see that in an answer choice it immediately raises a red flag. The reason for this is that only denotes a level of specificity that we usually don't want.

Hope this helps

[ohthatpatrick]

I loved most of that explanation; I just wanna make a couple points.

To return to the (A) vs. (B) debate, it sounds like the original poster was confident he/she wanted to hear something bad about the new test (or something that makes it on any level inferior to the current test).

Neither (A) nor (B) brings up anything about the current test, and all we know from the stimulus is that the current test sometimes fails to catch exotic cases of Salmonella.

So we'd have to compare (A) vs. (B) purely on the level of which one says something more detrimental to the new test's purpose: being used by public health officials to test food samples for Salmonella.

(A) says that the test would only identify Salmonella, not other bacteria. Is that a bad trait to have, in terms of evaluating this test as a method for public health officials to test food samples for Salmonella? No. It sounds fine. Why would I expect a Salmonella test to be good at finding other bacteria as well? As long as it finds the Salmonella, it has fulfilled its purpose as a Salmonella test.

(B) says that the test will identify Salmonella even at harmless levels. Is that a bad trait to have, in terms of evaluating this test as a method for public health officials to test food samples for Salmonella? Possibly. Maybe the new test is too sensitive to be practically useful, since it would sound the Salmonella alarm even when the food sample was safe. As the 2nd poster marvelously noticed, the stimulus says that the new test 'identifies the presence or absence', not necessarily the level of toxicity.

So even though (B) isn't a devastating problem (and, indeed, we might still prefer the new test that catches all cases, even if it means we have to run a follow-up test to determine toxicity), it is at least somewhat of a downside. (A) doesn't give us any downside, because 'other bacteria' are beyond the scope of this test's intended usefulness.

Finally, quick comment on red-flagging "only" on this question. It's a great LSAT habit in general to be wary of extreme words, but when question stems say,
Which of the following, if true, ..
Which of the following, if valid, ..
Which of the following, if assumed, ..

.. then I no longer am wary of extreme words. When the question stem hands us these ideas on a silver platter, we need only judge whether they serve their intended effect.

In fact, to the contrary, I am deeply suspicious of any answer choice on Strengthen, Weaken, Sufficient Assumption, Principle-Justify, or Resolve/Explain that uses watered-down language such as "some" / "many" / "not all".

[schmid215]

Thanks so much to the both of you!