This is a sufficient assumption question because the question stem says: “conclusion is properly drawn… which one is assumed?”
Sufficient assumption questions tend to be very formal. We’re looking for a rule that would 100% validate the conclusion, specifically by bridging the premise and conclusion through the rule. Not only are we extrapolating the rule from our argument, but we’re also using that rule to render the argument “valid.” The way to prephrase our answer choice is by tying our premises and conclusion together into a rule: “If [premise] → then [conclusion].” Sometimes though, rules are a little too chunky and don’t capture the gap accurately. This question is a great example of why.
The first sentence is pretty straightforward: photovoltaic power plants (PVP) create electricity through sunlight. We’re also told that it’s cheaper than it was 20 years ago and included the costs of construction and operation in this statement. The passage then notes that corresponding costs have increased for traditional power plants (TP). Okay, all good so far – the author is noting the change of costs for each separately.
The conclusion is that PVP is less expensive than TP. Wait – how can we draw a comparison between the two? We only know what’s going on with their respective costs. We can’t make a comparison between the two when we only know what’s going on within the two respectively. Let’s walk through this:
Imagine in 2003 the cost for PVP was $500. Since then, it’s decreased by 1/10, so the cost today is $50.
Now, for TP, in order for our conclusion to be true, the cost of TP in 2023 would have to be above PVP’s costs in 2023. So, something like: in 2003, the cost for TP was $600, and now the cost is $6000. (A note that “increasing” is a very vague term on the LSAT – we can’t really tell by how much something increased.)
But – does that have to be the case? NO!! It’s totally possible that the cost for TP was $20 in 2003, and then increased to $45. This goes against the conclusion. The problem here is that the premises are only giving information for comparison within the group, and our conclusion is about what’s going on between the groups. There is a mismatch.
If you’re having trouble seeing the comparison issue, let’s take another context. Let’s use the LSAT score as an example. What this argument is saying is the following... I took the LSAT twice and my score went up between those two takes. My friend also took the LSAT but her score went down from her first take. Therefore, I score higher on my LSAT than my friend did.
Is this conclusion valid? Not really - it could be that I went from a 150 to a 154; but my friend went from a 160 to a 159. This is the issue: having information about what’s going on with me and separately with my friend doesn’t allow for a conclusion comparing my score with my friend’s score.
Back to our argument, to close the gap here, a rule feels a little complicated. We need something explicit to address this gap. Something that draws a comparison between the two groups, not just within them. Something like, even 20 years ago, the cost for PVP was way lower than TP plants.
Answer Choice (A) This answer choice is just a repetition of what was stated in the stimulus above. A repetition of our stimulus isn’t going to help us out here.
Answer Choice (B) This isn’t correct – we don’t care about electricity produced 20 years ago. The technology could have improved and PVP produces much more; on top of this, the conclusion is about the cost of electricity now.
Answer Choice (C) Plugging this back into our stimulus will show how this is completely useless to our argument. This answer choice is basically saying that PVP and TP technology works in different ways; so, what? It’s possible to have two ways of doing something and both of them are great. This doesn’t make our conclusion valid.
Correct Answer Choice (D) We’re saying that even back then, PVP was 10 times less than TP. If PVP costs went down by a tenth and we also know that TP costs have increased, then we can properly draw our conclusion.
Answer Choice (E) Once again, we have more information about what’s going in within the groups and no information on what these costs are relative to each other.
This is a sufficient assumption question because the question stem says: “conclusion follows logically…if which one… is assumed?”
Sufficient assumption questions tend to be very formal. We’re looking for a rule that would 100% validate the conclusion, specifically by bridging the premise and conclusion through the rule. Not only are we extrapolating the rule from our argument, but we’re also using that rule to render the argument “valid.” The way to prephrase our answer choice is by tying our premises and conclusion together into a rule: “If [premise] → then [conclusion].”
Our first sentence is very straightforward: in bureaucracies, decisions involve many people. The sentence just elaborates on this by saying that no one person have more authority than the next person. These are both our premises.
Our conclusion states that in bureaucracies, risky projects are never undertaken. That’s a big jump! From “bureaucracy decisions involving multiple people” to concluding “risky projects are never undertaken”? What if that is the exact they take on risky projects? For example, they could say that because many people are involved, they’re able to prepare for every outcome.
In order for our conclusion to follow, we need to link up the idea in the premises to the conclusion: when multiple people are involved in decisions and no one has the authority, risky projects will not be taken.
Answer Choice (A) This isn’t correct. We’re trying to make our conclusion about risky projects not being taken on valid; the fact that projects always require risk doesn’t help the gap in our argument.
Answer Choice (B) This isn’t correct either. The gap here is that the argument assumes that have many people involved in a decision means that no risky project will be taken. If we plug this into our stimulus, this doesn’t help validate our conclusion. It could support it, but there are too many assumption we need to make to arrive to our conclusion.
Answer Choice (C) This is more or less what our premises are trying to say, but again, it’s not helping to validate our conclusion about risky project not being taken on in bureaucracies. Additionally, we’re not concerned with what groups of people will take risks - we specifically interested in bureaucracies who will not take risks.
Correct Answer Choice (D) We said we weren’t interested in people who take risks, but this is a conditional statement! The answer choice is saying “when risk take, then single individual power to decide.” Taking the contrapositive of this would be: if multiple people have the power to decide, the risk is not taken. See how “no risk taken” is in the necessary condition? This is the NC in our rule, and it’s also our conclusion. Our premises trigger the contrapositive of this answer and allow us to draw our conclusion.
Answer Choice (E) This isn’t correct; what people do on there own is outside the scope of their decision as a group. This doesn’t help us draw our conclusion.
This is a flaw question, and we know that because of the question stem: Which one of the following indicates a weakness in the position expressed above?
The author says that the United States has been used and is okay with a large defense budget used to fight against the Eastern bloc. However, the author says that Ince the threat along with the Eastern bloc is disappearing, the author concludes that it’s doubtful whether the public can be persuaded to support an adequate defense budget.
This argument may seem acceptable on surface level, but it’s important to hone in on certain modifiers and adjectives in this stimulus (as is often the case on the LSAT). In the first sentence, the author says that the defense budget is substantial. In the second, he says it’s adequate. Do those two mean the same thing? Especially with the Eastern bloc now dissolving, how do we know that an adequate budget and a substantial budget don’t mean entirely different things? This is where the argument falls short.
Answer Choice (A) is not descriptively accurate; the public isn’t being manipulated according to the argument. Instead, the argument speaks to the public being convinced of something.
Answer Choice (B) is not descriptively accurate either; there isn’t really a causal relationship being established in the argument; if there is, it’s that the eastern bloc caused the public to accept the defense budget, but that’s not what is wrong with the argument.
Answer Choice (C) is not descriptively accurate; the argument doesn’t as fact what it’s seeking to establish. If it was, this argument would feel very circular.
Answer Choice (D) is descriptively inaccurate; they do give a reason, it’s just not a very supportive premise for the conclusion reached.
Correct Answer Choice (E) is descriptively accurate and it’s a flaw. The way “substantial” and “adequate” are used isn’t clear. They could be mean different amounts of money, and the public could support an adequate budget without agreeing with a substantial budget.