Logical reasoning PrepTest 120 · Section 3 · Question 24

Incorrect. The stimulus doesn't establish that the city experienced an improving economy, so while this answer does provide an alternative cause of dropping crime rates, we don't know it applies here.

Incorrect. First, this answer is about "some crimes," so it's unclear if it's the same crimes as are included in the mandatory sentencing laws. Second, it isn't established how these unusually harsh sentences compare to the ones under the new law. We don't have enough information to know whether this answer choice affects the argument, so we can rule it out.

Incorrect. The premises in the argument are about violent crime, while the conclusion talks about "the drop in the crime rate." Assuming that the conclusion is talking about the overall crime rate, that's not actually a problem here, as a drop in a subset of crime is congruent with the overall crime rate decreasing. And even if the overall crime rate decreased by only 5%, that suggests that the decline in violent crime was in excess of the decline in overall crime, and some change must account for that. So, if anything, this answer aligns with the argument.

Incorrect. This "redefinition" answer is pretty common, and we should always start by figuring out if the new definition is broader or narrower than before. Here, it was broadened—which means that, if nothing changed, violent crime would be expected to increase since more things count as violent crime. However, it went down, suggesting that something was responsible for lowering that rate in the face of a broader definition. If anything, this strengthens the argument that there was a specific cause of that decline—this answer aligns with the conclusion.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Weaken

Stimulus Summary:
Last year, a new mandatory sentencing law went into effect and crime decreased 15%. Since no other policy changes happened, the law must have caused the decrease in crime.

Answer Anticipation:
Weaken questions frequently have correlation/causation flaws, so you should be on the lookout for them when you're dealing with this question type. Here, the conclusion states that a crime decrease "must have been due to" a new law, which is a causal statement. This is based on the law being correlated with the drop in crime, so we have our flaw!

When you're tasked with weakening a correlation/causation flaw, there are three common answer choice types:
(1) Identify an alternative cause (this argument rules out other policies, but there could be non-policy-based causes)
(2) Establish a counterexample (an area with similar laws that didn't see a decrease in crime; an area that saw a decrease in crime without a new law)
(3) Reversed causality (since the law preceded the drop in crime, this is almost certainly not going to be the correct answer)

Answer Explanation:
Sneaky! But we could have anticipated something like this (more on that in a minute). This answer provides an alternative cause. If there were more police officers on the streets, that may have led to the decrease in crime, not the new mandatory laws. This question is sneaky in that it states there were no changes in policy last year, but the correct answer then brings up a policy that was enacted before last year, but still caused changes this year. Timelines are generally relevant on LSAT questions, but in correlation/causation questions, it's generally related to the supposed cause and effect being temporally related. This answer plays with temporal issues in another way, but we definitely could have been primed to look for that based on the inclusion of a timeline in the stimulus.

Key Takeaway:
Go into Weaken (and Strengthen) questions looking for correlations and causal conclusions. You'll find them as often as not, and when you do, you can anticipate a specific set of answers in order to get you through the question efficiently.