#14 - In 1980, Country A had a per capita gross domestic

[lavalsat]

Hello,

I am wondering if someone could help me understand a certain piece of this question. Would't the assumption that the argument depends on be that "The per capita GDP of the EEC was not lower by $1,000 or more in 1990 than it had been in 1980?

If I am understanding correctly- the assumption, as stated in answer D, leaves open that possibility that the decrease of EEC GDP was EXACTLY $1,000 and therefore the standard of living in County A could have remained EXACTLY the same. Then this assumption as stated in answer D wouldn't necessarily be what the argument depends on, it would just strengthen the argument.

I am having trouble fully getting on board saying that the argument "depends" on this assumption. This one has me particularly confused!

[lavalsat]

In regards to my above comment, if I am correct that answer D leaves open the possibility that County A standard of living could have remained exactly the same, since this question asks for an assumption the argument depends on, is this answer choice technically flawed in its reasoning? If this answer choice is flawed (even if it is ever so slightly) why wasn't this addressed by LSAC? I would have much less of a problem if we were looking for an answer that supported the argument instead of one on which the argument depended on.

I guess my final two questions are:
1) Is the answer in choice D flawed?
2) If the answer is flawed, why did LSAC not address it or toss this question out?

[Adam Tyson]

Good question, lavalsat! If this was a Justify the Conclusion question, in which we needed to prove the argument was correct, answer D would indeed be insufficient, because we would also need to eliminate the possibility that EEC GDP did not drop by exactly $1000. But since this is an Assumption question, the correct answer doesn't need to prove the argument is correct. Rather, the argument has to prove the answer is correct!

There can be many assumptions in one argument. Here, the author has to make at least two:

1) EEC GDP did not drop by exactly $1000
2) EEC GDP did not drop by MORE than $1000

Both of those assumptions are necessary, although neither, by itself, is sufficient. The question doesn't ask for ALL the required assumptions, but just for one such assumption. Answer D is required, because if it was not true the argument would fall apart completely.

Here's a quick analogy:

I have never broken my leg. Therefore, I have never broken a limb.

What must I have assumed?

1) I have never broken my right arm
2) I have never broken my left arm
3) I have never broken some limb other than a leg

Answer 1 is a required assumption, even if it is not "complete" in the sense that there are still other required assumptions for the argument to be good. There's nothing wrong with that answer! The proof is that if I negate it - I HAVE broken my right arm - the argument turns out to be nonsense.

Be sure you aren't mixing up an Assumption question stem (aka Necessary Assumption) for a Justify the Conclusion stem (aka Sufficient Assumption). That may be where you got confused on this one.

[Camhaynes9]

Hi,

My confusion with this question is when the answer says more then $1000. If it were to drop by exactly 1000$. I know I’m missing something somewhere but to me this allows for the possibility that the per capita GDP drops by exactly 1000 making there be a 1000$ difference, and country A not having a better quality of life on avg because it stays the same. If it drops 1001$ then A must drop 1$ and if it drops 999$ then A must increase 1$ but if it drops 1000$ A stays the same and this makes this assumption incorrect as the GDP was not lower by more then 1000 and the quality of life in A does not increase.

I know I’m off somewhere but I was hoping for some guidance in where I am off.

[Jeff Wren]

Hi Cam,

I think that what is causing the confusion is understanding exactly what necessary assumption questions (which we just call Assumption questions) are asking and how they differ from sufficient assumption questions (which we call Justify questions). This confusion is very common among test takers and is one of the reasons that Assumption questions are often the most difficult question type for most test takers.

For a necessary assumption, the answer does not have to Prove the conclusion of the argument. Instead, what you need to ask when examining each answer choice is "Is this statement something that the person making the argument must believe in order for the argument to make sense."

For example, if I claim "My friend John is a great tennis player,"

An acceptable answer to a necessary assumption to this claim would be:

"John can hit the ball over the net."

Now just being able to hit the ball over the net is a long way from being a great tennis play. This definitely doesn't prove that John is a great tennis player and would therefore be a wrong answer in a Justify question.

But the question here isn't asking for an answer that proves the conclusion, just something necessary for the conclusion.

If you were to ask me "Can John hit the ball over the net?" I'd reply "Of course! That's so obvious that I didn't even bother mentioning it."

Similarly, in this question, the argument requires that "the per capita GDP of the European Economic Community was not lower by more than $1,000 in 1990 than it had been in 1980." If that statement were untrue, i.e. if "the per capita GDP of the European Economic Community was lower by more than $1,000 in 1990 than it had been in 1980," then the argument completely falls apart. The fact that this answer still allows the possibility that the per capita GDP of the EEC was lowered by exactly $1000 (in which case the conclusion would not be true) does not make it a wrong answer in the same way that "John being able to hit the ball over the net" still allows the possibility that he is not a great tennis player.

This is why using our Assumption Negation Technique (discussed in Lesson 5 of our course and the LR Bible) can be so helpful in handling these questions.

[madelineunruh01]

The wording of answer choice D tripped me up here. I think I would have gotten the question correct if answer choice D had said "the per capita GDP of the EEC was not lower by $1,000". But, since it said "lower than $1,000" that number then felt irrelevant to the stimulus. How do I reconcile the difference in language? It is so small that I want to say its a fluke and move on but I've learned to never ignore any singular word in an LSAT question because sometimes it makes or breaks the question...here it definitely broke it haha. Thanks!

[madelineunruh01]

The wording of answer choice D tripped me up here. I think I would have gotten the question correct if answer choice D had said "the per capita GDP of the EEC was not lower by $1,000". But, since it said "lower than $1,000" that number then felt irrelevant to the stimulus. How do I reconcile the difference in language? It is so small that I want to say its a fluke and move on but I've learned to never ignore any singular word in an LSAT question because sometimes it makes or breaks the question...here it definitely broke it haha. Thanks!

I can't edit my post but there is a typo. The answer choice reads "lower by MORE than 1,000" and not "lower than 1,000" as I incorrectly typed.

[Luke Haqq]

Hi madelineunruh01!

Since this is an assumption question, consider using the Assumption Negation technique to see how the wording of (D) applies to the stimulus. That involves negating the answer choice and plugging the result back into the stimulus; if this makes the argument fall apart, then it is an assumption on which the argument depends.

Here, the negation of (D) would be "The per capita GDP of the European Economic Community was [...] lower by more than $1,000 in 1990 than it had been in 1980." Note in the stimulus that the fact about Country A is defined in relation to the average GDP of the European Economic Community. The stimulus seems to be making an assumption that, because the difference had grown (by $1,000) between Country A and the average GDP of the European Economic Community from 1980 to 1990, the average standard of living must be higher. However, what if the European Economic Community's average GDP had lowered over that decade? If it had lowered by, say, $2,000, then the argument falls apart. It would not follow from the premises that the average standard of living is higher in Country A, because the greater difference in GDPs would instead be caused by a fall in GDP and standard of living.

This is what answer choice (D) gets at, and if the European Economic Community's average GDP had lowered by $1,001, the same reasoning would apply. That also seems to be true even if the amount were $1,000, but as Adam notes above, there can be multiple assumptions made by a stimulus; the task is to identify just one.

[askuwheteau@protonmail.com]

Hello,

I need clarification regarding how to solve #3 of the Numbers and Percentages problem set on page 584 of the 2023 LRB. This is the Country A to European Economic Community GDP problem.

Here's my reasoning:

A: Not a necessary assumption

B: Fails Negation Test

C: Not a necessary assumption

D: Meets negation test. When negated, undermines the integrity of the differential data ($5K spread in 1980 vs $6K spread in 1990) given in the stimulus's premise. For instance: In 1980 A's GDP is $100K and the EEC's is $95K=$5K. In contrast, in 1990, A's GDP is $101K and the EEC's is $95K= $6K.

If I lowered the EEC's 1990 GDP of $95K by more than $1K (i.e., to $93K), then the resulting spread would be $8K ($101K minus $93K=$8K. This would in turn violate the $1K spread stated by the stimulus's premise).

E: Fails negation test

Thank you in advance,

Jonathan Sloan

[Jeff Wren]

Hi Jonathan,

This question appeared on Preptest 16, the Sept. 1995 LSAT Section 2, question 14. We're going to move your question to that forum post so that others will be able to find it more easily. (I realize that you encountered this question in "The Logical Reasoning Bible" problem set, so there's no reason why you would have known this.) I recommend that you read the other questions and answers posted about this LR question, as there has been a lot of good discussion about this question that you may find helpful.

It's helpful to thoroughly analyze the argument in the stimulus and prephrase any assumptions before looking at the answers. Perhaps counterintuitively, one helpful way to identify assumptions in an argument is to actually look for weaknesses in an argument, as assumptions often eliminate those weaknesses.

Here, for example, knowing that Country A had a larger spread over the average EEC GDP in 1990 than in 1980 (a relative/comparative statement) tells us nothing about whether Country A's actual per capita GDP increased, decreased, or stayed the same during that time period. This is a classic numbers/percentage flaw. Here, the argument assumes that the per capita GDP for EEC did not drop by $1,000 or more. Having a solid prephrase of what the assumption being made in the argument is should save you time in sorting through the answer choices and hopefully reduce the need to use the Assumption Negation technique for most of the answer choices.

Regarding Answer D, I think that you have the right general idea, but may be going about it backwards (at least as you've written in your example.)

If we negate Answer D, that means that the per capita GDP of the EEC would have lowered more than $1,000. Let's use your example of dropping from $95k to $93k. At this point, it's not the spread that changes to $8k, as you've stated. The premises state that the per capita GDP for Country A was $6,000 more than the EEC in 1990, whatever the EEC per capita GDP is. So, if the EEC dropped to $93k, then Country A's per capita GDP in 1990 would be $99k (93 + 6). However, since $99k is less than $100k, which was Country A's per capita GDP in 1980 in your example, this would directly weaken the conclusion of the argument that the average standard of living had risen in Country A. Since per capita GDP is a measure/indicator of the average standard of living, a decrease in per capita GDP would indicate a decrease in the average standard of living rather than an increase.