Logical reasoning PrepTest 106 · Section 3 · Question 11

Flawed

Weaken Questions

Correlation - Increase in percentage of 18yo recruited into army and increase in high school drop-out rate

All 18yo are either grads or dropouts

Conclusion - Recruitment rates for 18yo rely on dropouts

Weaken questions tend to have Correlation/Causation flaws, so you should always be on the lookout for language suggesting that flaw in this question type. And this stimulus talks about correlations all over the place! However, the conclusion isn’t clearly causal, so we need to dig a bit deeper.

Let’s start with some basic questions - what’s correlated, and does the argument assume that one causes the other?

The correlation is between recruitment rates among 18yo and the dropout rate - they both went up around the same time. Does the argument assume that the recruitment rate caused the dropout rate, or vice versa? It does. While the conclusion states that the recruitment rate depends substantially on the dropout rate, that’s assuming that the dropout rate drives the recruitment rate. As such, it’s assuming, essentially, that an increase in the dropout rate will cause an increase in the recruitment rate for 18yo. It’s not a perfectly causal argument, but it’s close enough that we can look for the standard answers:

Identify an alternative cause Counterexamples (cause without effect; effect without cause) Reverse causality (which makes sense here - maybe an increase in recruitment led 18yo to drop out because, say, the army was paying very well)

Let’s find one of these answers.