PT28.S3.Q11 - A rise in the percentage of all 18-year-olds who...

Ashley2018-1

Is this a correlation-causation argument because it assumes that the increase in high school dropouts is the only thing that is causing the increase in recruitment among 18 year olds? And why would the author draw such a conclusion?

And I know there's an explanation vid for this, but why is A incorrect? If the conclusion had said "solely dependent" on high school dropouts, would A weaken?

Admin Note: https://7sage.com/lsat_explanations/lsat-28-section-3-question-11/

Bagelinthemorning-2-1-1

Hey @Ashley25,

You are correct! The author is making a causation argument based on two occurrences that coincide. The conclusion states that the republic's recruitment rates for 18 years olds requires recruitment rates for high school drop outs. The loophole we want here is one that shows that the high school drop outs have nothing or little to do with the recruitment rates.

Choice A says that the graduates had a higher recruitment in '86 than '80. This answer choice doesn't weaken the premise-conclusion link for two reasons. (1) Larger number could mean anything from +1 to +1000, and that doesn't mean it makes the majority, and (2) It could still be that a larger number of graduates were recruited (compared to '80), and the high school drop outs could still be the primary source of recruitment. Because of these reasons, answer choice A is incorrect.

Choice C is correct because it deals with the percentage (not the number like answer choice A). It makes an argument that graduates make a higher percentage of the recruits, which weakens the premise-conclusion link above.

Ashley2018-1

@Bagelinthemorning said:
Hey @Ashley25,

You are correct! The author is making a causation argument based on two occurrences that coincide. The conclusion states that the republic's recruitment rates for 18 years olds requires recruitment rates for high school drop outs. The loophole we want here is one that shows that the high school drop outs have nothing or little to do with the recruitment rates.

Choice A says that the graduates had a higher recruitment in '86 than '80. This answer choice doesn't weaken the premise-conclusion link for two reasons. (1) Larger number could mean anything from +1 to +1000, and that doesn't mean it makes the majority, and (2) It could still be that a larger number of graduates were recruited (compared to '80), and the high school drop outs could still be the primary source of recruitment. Because of these reasons, answer choice A is incorrect.

Choice C is correct because it deals with the percentage (not the number like answer choice A). It makes an argument that graduates make a higher percentage of the recruits, which weakens the premise-conclusion link above.

Do you mean just because there's an increase in the number of high school graduates among the recruited doesn't mean that there was an overall rise in the percentage of 18 year olds recruited? For example, in 1980, there were 10 high school graduates recruited and in 1986, there were 20 ("larger number of high school graduates") but both could still make up the same percentage within the group of 18 year olds recruited ("either high school graduates or dropouts")

1980: 1000 people recruited
100 are 18 year olds
10 high school graduates (10%)

1986: 1000 people recruited
200 are 18 year olds (doubled)
20 high school graduates (still 10%) so increase in percentage could still be due to high school dropouts

and that's assuming these numbers hold because this answer choice only talks about 1980 and 1986 and not 1980-1986. maybe there were 0 high school graduates recruited in between so it makes it even less likely the rise in percentage of 18 year olds was due to graduates, even if the numbers went up in 1986 compared to 1980

nnnnnnzzzz

You are right the AC A has a percentage v. number flaw. An increase in number doesn't always equal an increase in percentage or vice versa.

Back to the sitmulus, there could be no correlation whatsoever. Rise in percentage of young people who dropped out of highschool can include freshmen, sophomores, juniors, and seniors (18 year old).

With C we know that the percentage of highschool graduates (18 year old) rose which means percentage of highschool dropouts actually decreased. It is safe to assume this because (1) the premise said 18 year olds can only be either graduates or dropouts, and (2) percentage is always equal to 1 or 100% and a decrease in one guarantees an increase in another.

Taken C as true, then the rise in percentage of young people who dropped out high school is due to other class standings and not those who are 18 year olds.

Bagelinthemorning-2-1-1

Hi @Ashley25,

Yeah, I agree. The numbers increasing by 10 doesn't mean that they make up the larger percentage of the pie. The percentage may only increase (let's say by 10%) but we are looking for an increase that makes the majority (compared to drop-outs). Therefore, when the answer choice says graduates make a higher percentage of the recruits compared to drop-outs, it weakens the argument that drop-outs constitute the majority.

Ashley2018-1

@Bagelinthemorning said:
Hi @Ashley25,

Yeah, I agree. The numbers increasing by 10 doesn't mean that they make up the larger percentage of the pie. The percentage may only increase (let's say by 10%) but we are looking for an increase that makes the majority (compared to drop-outs). Therefore, when the answer choice says graduates make a higher percentage of the recruits compared to drop-outs, it weakens the argument that drop-outs constitute the majority.

Reviving this thread: I've seen many comments stating that it's problematic to choose an answer choice involving absolute numbers when approaching a stimulus involving changes in percentages....but why is that the case?

nnnnnnzzzz

@Ashley25 said:

@Bagelinthemorning said:
Hi @Ashley25,

Yeah, I agree. The numbers increasing by 10 doesn't mean that they make up the larger percentage of the pie. The percentage may only increase (let's say by 10%) but we are looking for an increase that makes the majority (compared to drop-outs). Therefore, when the answer choice says graduates make a higher percentage of the recruits compared to drop-outs, it weakens the argument that drop-outs constitute the majority.

Reviving this thread: I've seen many comments stating that it's problematic to choose an answer choice involving absolute numbers when approaching a stimulus involving changes in percentages....but why is that the case?

It's because the assumption that an increase/decrease in number is equal to an increase/decrease in percentage is a classic flaw. It has not always been the case.

Ashley2018-1

@nz889910 said:

@Ashley25 said:

@Bagelinthemorning said:
Hi @Ashley25,

Yeah, I agree. The numbers increasing by 10 doesn't mean that they make up the larger percentage of the pie. The percentage may only increase (let's say by 10%) but we are looking for an increase that makes the majority (compared to drop-outs). Therefore, when the answer choice says graduates make a higher percentage of the recruits compared to drop-outs, it weakens the argument that drop-outs constitute the majority.

Reviving this thread: I've seen many comments stating that it's problematic to choose an answer choice involving absolute numbers when approaching a stimulus involving changes in percentages....but why is that the case?

It's because the assumption that an increase/decrease in number is equal to an increase/decrease in percentage is a classic flaw. It has not always been the case.

@Bagelinthemorning said:
Hey @Ashley25,

You are correct! The author is making a causation argument based on two occurrences that coincide. The conclusion states that the republic's recruitment rates for 18 years olds requires recruitment rates for high school drop outs. The loophole we want here is one that shows that the high school drop outs have nothing or little to do with the recruitment rates.

Choice A says that the graduates had a higher recruitment in '86 than '80. This answer choice doesn't weaken the premise-conclusion link for two reasons. (1) Larger number could mean anything from +1 to +1000, and that doesn't mean it makes the majority, and (2) It could still be that a larger number of graduates were recruited (compared to '80), and the high school drop outs could still be the primary source of recruitment. Because of these reasons, answer choice A is incorrect.

Choice C is correct because it deals with the percentage (not the number like answer choice A). It makes an argument that graduates make a higher percentage of the recruits, which weakens the premise-conclusion link above.

One thing I've noticed about reading answer choice A is that it cites only 1980 and 1986 rather than the years in between but the stimulus is about a correlation that takes place in between the years 1980-1986...does that matter?