Logical Reasoning

PT106 · S3 · Q11 A rise in the percentage of all

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A rise in the percentage of all 18-year-olds who were recruited by the armed services of a small republic between 1980 and 1986 correlates with a rise in the percentage of young people who dropped out of high school in that republic.

Conclusion

The republic's recruitment rates for 18-year-olds depend substantially on recruitment rates for high school dropouts.

Evidence

There was a correlation from 1980 and 1986 between an uptick in the % of 18-year-olds recruited by the armed services and an uptick in the % of young people who dropped out of high school.

18-year-olds are generally either high school graduates or high school dropouts.

Evaluate

Since the evidence is presenting a changing statistic, and the conclusion is assuming a causal explanation for that statistic, we can use our Explain Curious Fact mindset:

Curious Fact ... why was there an uptick in the % of 18-year-olds recruited into the armed services between 1980-1986? (why was this correlated with an uptick in % of 18-year-olds that were dropouts?)

Author's Explanation.... the armed forces try hard to recruit high school dropouts, so during this period when there were more high school dropouts, they were able to recruit more 18-year-olds into the armed services.

We can Weaken an Explain Curious Fact argument two ways: 1. (more common) suggest an Alternate Explanation for the curious fact 2. hurt the plausibility of the Author's Explanation

Any time an author presents a correlation between X and Y and then assumes/concludes that X causes Y, we're supposed to reflexively consider these two Alternate Explanations:

- could it be Reverse Cause (in this case -- could the rise in recruits have come first, and that somehow inspired more 18-year-olds to drop out?)

- could there be some Third Factor responsible for both? (maybe a foreign invading army is causing people to drop out of school and sign up for the military)

Goal

Look for an alternate way to explain the correlation between more dropouts and more armed service recruits.

Or look for a way to hurt the story that the armed services go after these high school dropouts.

11.

Which one of the following statements, if true, most weakens the argument?

  1. A larger number of 18-year-old

    Relative vs. Absolute

    This has unclear impact, because it's talking about number whereas the argument is all about percents, so the raw number isn't important. It's possible that the population overall is growing in number, so there are more graduates, more dropouts, more recruits no matter what. The author is specifically trying to figure out why a bigger share of 18-year-olds was recruited in 1986 than in 1980. This answer might otherwise be tempting, since it sounds like more and more high school graduates are being recruited, whereas the author is trying to explain the uptick in recruits by pointing towards dropouts being recruited.

    8% picked this

  2. Many of the high-technology systems

    Weaker Impact

    This does weaken somewhat, by attacking the plausibility of the idea that the army is chasing after high school dropouts as potential recruits. This answer pushes back, like, "Why would they want dropouts? Many high-tech systems in the army require a high school education". That definitely has some impact, but it's watered down by the strength of many, and by the fact that operating high-tech systems might be a really atypical job in the military. In other words, this answer is saying, "There are at least a handful of high-tech systems that require high school graduates to operate them". That definitely convinces us that the entire armed services can't be made up of dropouts. But it still leaves room for 99% of service members to be dropouts since we might only need about 100 high school graduates to operate these specific high-tech systems.

    19% picked this

  3. Correct

    Between 1980 and 1986 the

    Why this is right

    This offers an Alternate Explanation for the Curious Fact, which is the #1 thing that correct answers do when we're weakening an Explain Curious Fact style argument. The author is wondering what accounts for the rising % of 18-year-olds recruited by the armed services. Let's assign a couple numbers to this change in recruitment rate, just to ground this in something specific. 1980 1986 % of 18-year- 20% 30% old recruited During the same time, there was a change in the dropout rate. 1980 1986 % of 18-year-olds 5% 10% who dropped out The author assumes these two statistics are related, and that the armed services recruited a bigger share of 18-year-olds because there was a bigger share of 18-year-olds that were dropouts. This answer offers an alternate explanation. It tells us that from 1980 - 1986 the % of high school graduates being recruited rose sharply. Maybe in 1980, only 15% of high school grads were recruited, and now in 1986 it's more like 35% of high school grads are recruited. That big increase in the share of 18-year-old graduates being recruited could explain why a bigger share of 18-year-olds were recruited. (Naturally, it could also be true that a bigger share of dropouts were recruited, and the uptick in recruiting grads and dropouts may have combined to account for the rising share of 18-year-olds that were recruited). But that doesn't change the weakening effect. An Alternate Explanation isn't weakening by showing that the Author's Explanation is wrong. It weakens by showing we don't need the author's explanation in order to explain the curious fact. Thus, the answer is wrong to move with such overconfidence from observing the curious fact to concluding his particular causal explanation (when other possible causal explanations exist).

    Skill tested: Weaken · how this choice captures the argument's function is the move to repeat next time.

    65% picked this

  4. Personnel of the republic’s armed

    Strengthens, if anything

    If armed services personnel are being encouraged to finish their high school education, then by definition those personnel are not high school graduates (thus they are dropouts). So this answer is acknowledging the existence of armed service personnel who are dropouts. That would strengthen the argument, if anything.

    4% picked this

  5. The proportion of recruits who

    No Impact: 2+ years of college

    We can't do anything with a factoid about people who completed "at least 2 years". They might be dropouts. They might be graduates. Who knows. They probably aren't 18-year-olds, since most people don't enter their first year of college until 18. So this answer is talking about a group of people that aren't 18-year-olds, and we can't even tell what proportion of them are graduates vs. dropouts.

    4% picked this

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