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

[Administrator]

Complete Question Explanation

Assumption—Numbers and Percentages. The correct answer choice is (D)

     This is a challenging question. The author makes the following argument:

     Premise: In 1980, Country A had a per capita gross domestic product (GDP) that was
     $5,000 higher than that of the European Economic Community.

     Premise: By 1990, the difference, when adjusted for inflation, had increased to $6,000.

     Premise: A rising per capita GDP indicates a rising average standard of living.

     Conclusion: The average standard of living in Country A must have risen between 1980
     and 1990.

The author has fallen into the trap of believing that an increase in the difference between GDP’s
means that the actual GDP of Country A has increased. Since that is not necessarily the case based
on the difference, you should look for the answer that assumes the total GDP of country A has not
decreased.

Answer choice (A): The stimulus is clear that the GDP is a “per capita” (per person) figure. Hence,
the author does not need to make an assumption regarding actual population increases.

Answer choice (B): The author does not need to assume this is true because a bigger GDP gap
does not prove that either must have fallen; the actual GDP of both Country A and the European
Economic Community (EEC) could rise and the author’s argument would still be valid.

Answer choice (C): In the argument the author uses the GDP of the entire EEC. Since the figure for
the EEC would necessarily be an average drawn from the numbers of multiple countries, the author
does not need to make any assumptions about figures for individual countries within the EEC.

Answer choice (D): This is the correct answer. In order to conclude that an increasing difference
in GDP translates to an actual increase in GDP, the author must assume that the GDP of the point
of comparison, the EEC, did not fall dramatically. Consider the following example, which assigns
actual numbers to the GDP of each group in 1980, and then shows a variety of possibilities for the
numbers in 1990 (two of which are inconsistent with the author—can you spot the two?):

Capture.PNG

Each of the four examples for 1990 is consistent with the claim that there is a $6000 (6K) difference
between the GDP of Country A and the GDP of the EEC. The first two examples for 1990—#1 and
#2—show that the GDP of Country A, and therefore the standard of living as defined in the stimulus,
has risen. Example #3 shows that even though the gap has increased between the two groups by
$6000, the actual GDP of Country A has decreased, and therefore the standard of living in Country A
has decreased. This is inconsistent with the author’s conclusion, so the author must be assuming that
this type of scenario cannot occur. In example #4, we see another example that is incompatible with
the author’s conclusion, one where the gap remains at $6000, but the GDP of Country A remains the
same (at 105K). The author must assume that the fourth scenario also cannot occur, and that the GDP
of the EEC cannot drop by the $1000 that is the amount of the increase in the gap. Hence, the author
must assume that if the GDP of the EEC drops, it drops by less than $1000, and therefore answer
choice (D) is correct.

This is clearly a confusing answer, but do not forget that you can always apply the Assumption
Negation Technique to any answer choice in an Assumption question. Answer choice (D), when
negated, reads: “The per capita GDP of the European Economic Community was lower by more
than $1,000 in 1990 than it had been in 1980.” This negation would definitely weaken the argument
because it would create a scenario like #3 or one even worse than #4. Because the answer choice
weakens the argument when negated, it must be the correct answer.

Answer choice (E): This answer is incorrect for the same reason cited in answer choice (C): since the
figure for the EEC would necessarily be an average drawn from the numbers of multiple countries,
the author does not need to make any assumptions about the figures for individual countries within
the EEC, regardless of year.

[maximbasu]

Hello,
I chose A as the correct answer while the correct answer was D.

I don't understand what D is saying. I reasoned A is correct, because if the populations increased at the same percentage, then the GNP would be constant and that would be the assumption.

Thank you, Maxim.

[Jon Denning]

Hey Maxim,

Thanks for the question! This one actually revolves around a somewhat tricky numbers and percentages idea that you're likely to encounter again at some point, so let me try to break it down for you.

First, let's understand the difference between a rising amount and a rising relative amount (an increasing difference in two amounts, in other words). A numerical value going up, like someone's salary, say, or a country's overall GDP, is straightforward enough. More is more.

A little less straightforward is a notion like a rising GDP per capita where you could achieve it a few different ways: since it's measured per person, the overall amount could increase, the number of people could decrease, or some combination of those two could occur. That is, if your country brings in $1 million a year and has 1,000 people, that's $1,000/person. How can you up that number per person? (1) Make more money, like $2 million a year for those 1,000 people for $2,000 each, (2) distribute the total amount to fewer individuals (population shrinks), like $1 million a year to only 500 people for $2,000 each, or (3) some form of both. What we know is that at least one of those two things--more money or fewer people--must happen.

Slightly trickier still, to many people at least, is the idea of relative, or comparative, change: in this case comparing Country A's per capita GDP to that of the EEC over time. A's was $5,000 more in 1980, and rose to $6,000 more in 1990...but what can we really know with certainty from that? In other words, does that guarantee that A's GDP actually increased? Nope! The alternative is that the EEC's GDP per capita decreased, and that accounts for the larger gap between them. So you have two ideas at work: the varying ways that a per capita GDP of some group can change, AND the comparative nature of two GDPs related to each other over time.

So what must we show for the conclusion that Country A's per capita GDP, and thus its standard of living, rose from 1980 to 1990? We need to rule out the alternative possibility suggested above (the other possible cause of the increasing gap between A and EEC): we need to show that the EEC's GDP didn't go down and create the larger difference. That's exactly what answer choice (D) does, so it is correct.

Answer choice (A) on the other hand has no effect here. If both populations increased at the same rate the only thing that even begins to impact (and it still doesn't, really) is the individual GDPs of Country A and the EEC, for reasons mentioned in the paragraph above about per capita change. This argument though is about the comparison between A and the EEC and whether that proves A's per capita GDP increased, so the right answer needs to address the difference in the years measured. (A) doesn't.

I hope that helps!

Jon

[maximbasu]

Thank you very much Jon, I understand it now!

Maxim

[Johnclem]

Hello,
for answer choice A , if there was a difference in the population of the two countries, - where country A's population did decrease would that make this choice correct then? ( Since the decrease in population would mean there was an increase in GDP)


Thanks
John

[Jonathan Evans]

Hi, John,

Good question, and if you don't mind I will briefly digress to observe that thinking about LSAT counterfactuals represents among the most challenging of thought experiments because once we depart from the test as it is written, we often end up in liminal gray zones in which arguments can be made for one position or another, or sometimes both. Therefore, it is difficult definitively to assert that had an answer choice been written differently it would have been a valid response.

With respect to your question, the short answer is no. It is not necessary for the author to assume that the population decreased by a certain amount compared to that of the EEC. Further, any given decrease or increase in population of either Country A or the EEC is in fact irrelevant to the flaw in the reasoning of this argument. As Jon noted, we are only concerned with GDP per capita. Irrespective of the overall population, we know from the premises that "a rising per capita GDP indicates a rising average standard of living." Even if the overall GDP fell, it would be possible to have an increased standard of living given a sufficiently large decrease in population. Even if the overall GDP rose, it would be possible to have a decreased standard of living given a sufficiently large increase in population.

I hope this explanation was not too convoluted and helped to shed some light on these concepts for you.

[amagari]

i believe in the post, you mentioned we don't need to actually do any calculations. How would we be able to go through all the stuff explained above on the test without doing some calculations?

Do you know some other questions like this so we can practice dissecting the numbers??

Thanks

[nicholaspavic]

i believe in the post, you mentioned we don't need to actually do any calculations. How would we be able to go through all the stuff explained above on the test without doing some calculations?

Do you know some other questions like this so we can practice dissecting the numbers??

Thanks

Hi amagari,

To answer your first question, as test-takers, we just need to realize that there may be a decrease in the EEC while Country A's GDP remains the same. Although the examples above use actual numbers, that is for illustration purposes (it helps some people to think in hard numbers, for others it's the opposite.) If you have an easier time considering just the relative positions without actual numbers, please go with what you are comfortable with!

As far as more examples, it depends on the materials which you have access to. In the full course materials, more examples may be found in Lesson 9. In the LR Bible, I believe Chapter 17 contains the Numbers and Percentages material.

Thank you for the great questions!

[nusheenaparvizi]

Slightly trickier still, to many people at least, is the idea of relative, or comparative, change: in this case comparing Country A's per capita GDP to that of the EEC over time. A's was $5,000 more in 1980, and rose to $6,000 more in 1990...but what can we really know with certainty from that? In other words, does that guarantee that A's GDP actually increased? Nope! The alternative is that the EEC's GDP per capita decreased, and that accounts for the larger gap between them. So you have two ideas at work: the varying ways that a per capita GDP of some group can change, AND the comparative nature of two GDPs related to each other over time.

Could someone please expand on this idea Jon mentions further? I have been trying to reread it to get close to understanding why D is correct but I think my main problem is I have no idea what answer choice D is even saying. If someone could explain in the simplest terms possible what the answer choice is saying and then expand on what Jon is saying when he mentions "the alternative is that the EEC's GDP per capita decreased and that accounts for the larger gap between them," I'd really appreciate it.

Thank you so much!

[Adam Tyson]

Happy to do so, nusheenaparvizi!

Imagine a similar, but simpler, scenario. Last year, my wife earned $10,000 more than I did. This year, she earned $15,000 more than I did. Now, did she make more money this year than she did last year? Maybe, or maybe not. Maybe the reason her income was relatively higher compared to mine this year than last year is because my income went down this year, while hers stayed the same? Maybe I lost my job, or worked fewer hours?

To prove that my wife actually DID earn more this year than she did last year, it would help to know that my income wasn't a lot lower this year than last year. If I made the same amount as last year, then she must have made more in order to widen that gap between our incomes. If I made just a little bit less, she would still have had to earn more in order for the difference between us to increase that much. If my income increased, then for sure hers would had to have increased in order for her to be making that much more than me. So what would I have to assume in order to conclude that her income did in fact rise by at least some amount? That my income did not decrease by $5000 or more compared to my income last year.

The stimulus is all about GDP increases in one place compared to GDP in another place. To be certain that increase wasn't just by comparison, but actually represented a real absolute increase, we have to assume that GDP in the other place didn't go down a bunch.

And finally, to put it another way, answer D is all about eliminating a possible alternate cause for the relative increase in GDP. If it was not caused by the GDP going down in the EEC, then it must have been caused by it increasing in Country A.