LSAT 157 - Section 2 - Question 03

Which one of the following would most logically complete the argument above?

This is a Fill in the Blank Question, with the sub-type Main Conclusion-Most Strongly Supported. We know this because the question stem asks us for what would “most logically complete the argument” above, and the blank in the stimulus follows the language, “We should conclude that use of these pesticides …”

Let’s read the stimulus to see what we’re told about pesticides and their use.

The first sentence begins with what seems to be a potential concession:

Although there are immediate short-term gains in crop yield from a single application of certain hydrocarbon-based pesticides to fields on which they have not been previously used, …

By using “although,” the author of a stimulus commonly introduces a point that she concedes is true, but signals that she will shift direction to focus on something else, or introduce a contrast.

That’s exactly what’s happening here. The author acknowledges that if we use certain pesticides on fields they haven’t been used on before, there are short-term gains in crop yield. This means that we will be able to harvest more crops, at least in the short time after we use the pesticide. That seems like a good thing, right?

Not so fast – we are about to get the contrast:

… studies have shown clearly that long-term use gradually depresses crop yield from this initially elevated level.

Long-term use of the pesticide (as opposed to the first-time use on a field that the pesticide hasn’t been applied to) will decrease crop yield after the initial increase. So long-term use of the pesticide isn’t so great for crop yield.

Notice, however, that it doesn’t say that long-term use of the pesticide brings crop yield down to below where it was before we started to use the pesticide. It only says that it brings crop yield down to below the “elevated level” immediately after the short-term pesticide use.

Thus, we should conclude that use of the pesticides ___________.

What makes sense to put in this blank? Well, since the previous line emphasized the long-term impact of pesticides on crop yield, we can expect the answer to relate to that impact.

Answer Choice (A) is uneconomic

This is a tempting trap answer. Although long-term use of the pesticide decreases crop yield from the higher level that we see immediately after short-term pesticide use, that doesn’t mean use of the pesticide is uneconomic overall. The judgment that something is “uneconomic” involves all sorts of other factors – how much does it cost to use the pesticide? Is the extra short term crop yield worth more than whatever decrease occurs after long term use? What if in the short-term we can sell so many more crops that using the pesticide ends up being economically justifiable? This is why we can’t conclude that use of the pesticides is uneconomic.

Answer Choice (B) damages the environment

Remember, we’re trying to fill in the blank that follows these particular statements in the stimulus. We’re not just trying to pick something that you think is true about pesticides. It doesn’t matter whether it’s reasonable to think that pesticides damage the environment – maybe it is, maybe it isn’t. I’m not going to engage with that question. What matters is that the stimulus didn’t say anything about environmental damage; it mentioned the pesticide’s impact on crop yield. That’s it. So the correct answer should be something that can be tied to the impact on crop yield.

Answer Choice (C) will eventually make pest problems unmanageable

Can you point to any line in the stimulus that suggests the pesticide will make pest problems unmanageable? The stimulus simply spoke about the short term and long term effects of the pesticide on crop yield – the amount of food you get from the crops. So we have no basis to conclude something about pest problems.

If you chose (C), ask yourself why? I have two hypotheses. One is that, similar to (B), you might have simply relied on information you knew from the world. You might have read news stories about overuse of pesticide giving rise to pesticide resistant pests. Sure but that’s not information in the stimulus. My other guess is that you may have been trying to explain why crop yields gradually decrease. You might have hypothesized that it’s because of pesticide resistance. But that hypothesis is far too speculative. Sure, it’s a possible hypothesis but there are way too many possible hypotheses. For example, consider (D).

Answer Choice (D) is probably not occurring in accordance with manufacturers’ instructions.

This too is a possible explanation of the gradual decrease in yields. But just like (C), it’s far too speculative. We don’t know what the manufacturer’s instructions said, nor can we guess about it. Did the farmers follow those (unknown to us) instructions? Who knows? None of the statements in the stimulus refers to instructions or anything that would be evidence of those instructions.

Correct Answer Choice (E) gives financial returns that diminish over time

This is a pretty tough correct answer. The LSAT knows that you’re looking at the phrase “financial return” and thinking that the stimulus didn’t mention that. And they’re hoping that you then pick something like (A) or (B). But what you’re ignoring is that the sentence immediately before the concluding blank was about the short term and long term effects of the pesticide. There’s a spike in crop yield in the short term, but in the long term, the level of crop yield “gradually decreases.” The blank that we’re trying to fill in is a conclusion that follows from that statement.

With that in mind, (E) follows from stimulus’s claim that the level of crop yield “gradually decreases.” Over time, after the initial increase, the crop yield will go down. Will decreased crop yield mean diminished financial return? Yes – why do farmers grow crops? To sell them. In the context of this stimulus, that is a highly reasonable assumption. So if they start to get fewer and fewer crops from the fields on which the pesticides are used, then they’re selling fewer and fewer crops from those fields. This means the return they’re getting from the pesticides is diminishing.