Logical Reasoning

PT120 · S3 · Q24 Police commissioner: Last year our

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Police commissioner: Last year our city experienced a 15 percent decrease in the rate of violent crime.

Conclusion

The new mandatory sentencing law caused the drop in the crime rate.

Evidence

The new law was enacted at the beginning of the year. No other major policy changes were made last year. Last year's crime rate was 15% lower than the previous year's.

Evaluate

Since the author is looking at a statistical change (-15% on crime rate) and then concluding what caused it, we can use our Curious Fact / Explanation mindset.

Curious Fact ... why did the crime rate go down by 15%? Author's Explanation ... the new mandatory sentencing law caused there to be less crime (presumably because mandatory jail time was enough of a deterrent that it scared off 15% of violent criminals from committing a crime)

We always ask the same two questions of these: - could there be some other way to explain the curious fact? - how plausible is the Author's Way?

Could the 15% drop be from a population decline? From a boosting economy? From a pandemic?

Is it plausible that some potential violent criminals knew about the enactment of the mandatory sentencing law and considered it enough of a deterrent that they refrained from committing a violent crime?

Goal

Since this is Weaken, our #1 prediction is that we'll see an answer suggest an Alternate Explanation for why the crime rate went down 15% last year, but we'll keep our minds open for an answer that undermines the plausibility that would-be criminals were deterred by this new sentencing law.

24.

Which one of the following, if true, most seriously weakens the police commissioner's argument?

  1. Studies of many other cities

    Unclear Impact

    This type of idea vaguely suggests that the crime rate could be dropping from improving economic conditions. But we were never told that this city has improving economic conditions, so we would be totally speculating whether this answer choice is relevant to this city's crime rate drop.

    9% picked this

  2. Prior to the enactment of

    Unclear Impact

    This isn't giving us any distinction about last year that would allow us to come up with an Alternate Explanation for the crime drop. But, could we say that this undermines the plausibility of the Author's Story? She's selling us on the idea that a law that mandates jail time for violent criminals was a meaningful change that deterred 15% of violent crime. If this city was already imposing unusually harsh penalties, though, is this mandatory sentencing law even going to be a meaningful change? What criminal would be deterred by a mandatory sentencing law if they're already expecting unusually harsh penalties from local judges? The problem is the vagueness of "unusually harsh penalties for some crimes". Do they include the violent crimes that this mandatory sentencing law addresses? Without knowing, there's no way to judge whether this has any impact.

    12% picked this

  3. Last year, the city’s overall

    No Impact

    Since the mandatory sentencing law only dealt with violent crime, we're not expecting it to have any effect on overall crime. Given that we know violent crime went down by 15%, if an answer tells us that overall crime went down by 5%, that means that nonviolent crime went down by less than 5% (it may not have gone down at all / it may have even increased). But we really don't care about nonviolent crime.

    2% picked this

  4. At the beginning of last

    Strengthens, if anything

    This provides a factor that would lead to an increase in the violent crime statistic. Had this answer said that last year the police department's definition of "violent crime" was narrowed to exclude 2 crimes that were previously called "violent", it could serve as an alternate explanation for the 15% crime rate drop.

    16% picked this

  5. Correct

    The city enacted a policy

    Why this is right

    This gives us an Alternate Explanation for the the 15% crime rate drop -- there were 100 new police officers hired last year. This answer sneaks around the constraint that "no other major policy changes were enacted last year" by telling us about a policy change enacted 2 years ago that still has new ramifications last year. This answer, like all Alternate Explanations, involves us using some real world causal common sense. #DefundThePolice notwithstanding, if you asked 10 people on the street whet "adding more police officers could help to decrease the violent crime rate", most would say "of course that could happen".

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

    61% picked this

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