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February 21, 2021

Valuable accountings of crime trends present and past

My morning surfing led me to two notable new pieces with oceans of interesting information about crime and all the debatbale accounts for why it has gone up and down in the United States. Here are links and short excerpts from lengthy pieces which both merit a full read:

"What Drove the Historically Large Murder Spike in 2020?  The pandemic, police violence, and more guns all contributed to an unprecedented rise in murders across the United States" by Rob Arthur and Jeff Asher at The Intercpt.  An excerpt:

Any explanation for the national spike in homicides in 2020 needs to account for why most U.S. cities saw an increase, and the available evidence suggests that we should avoid simplistic or local explanations to explain what was almost certainly a complex national phenomena. Murders were up at least 15 percent through September in cities of every population group, according to the FBI’s data, and the change in murders was larger in towns with under 10,000 people (up 31 percent) than in cities with over 1 million people (up 29 percent). Murders rose dramatically in big cities like New York and Chicago, but smaller cities like Lubbock, Texas, and Shreveport, Louisiana, also recorded their highest murder counts in decades.

The available evidence suggests that we should avoid simplistic or local explanations to explain what was almost certainly a complex national phenomena.

Identifying the change in the murder rate is relatively easy compared to figuring out why the increase occurred. The data suggests that 2020’s murder increase can best be thought about as three separate rises.  A deeper dive into where and when murder increased shows a number of contributing factors: a challenge to police legitimacy and the strain of the pandemic, exacerbated by a sudden surge in the use of firearms in several cities.

"The Great American Mystery Story: Why Did Crime Decline?  To stop the COVID crime wave, we must understand why crime declines: 25 explanations for the Great American Crime Decline and what it means for today" by John Roman at Substack:

25 Reasons Why Crime Declined in America

So now, finally, we have arrived at the point where I can describe the most important theories about why crime declined.  This list is a little bit of a labor of love in that I have been curating it for twenty years.  I didn’t offer any judgments about the relative merits of the Zimring claim that changes in police practices explain the crime decline or the Levitt claim that it is the sheer number of police that matter.  In fact, I think both theories have substantial merit.

And so to do all of the other items on this list.  For each, I have provided a link to a paper that rigorously makes a compelling claim for the idea.  In fact, having a list of 25 explanations for the crime decline was completely arbitrary — I could have added at least a dozen more (and in fact my list here is more like 35 theories since I have grouped some similar ideas and snuck in a few extra).

So, without further ado, here is the list.  The first bunch of causal mechanisms for the crime decline has been explicitly linked by researchers to the crime decline and the link makes that connection.  The rest of the ideas on the list are mechanisms that mediate criminal behavior.  I am linking these mechanisms to the crime decline because changes in the extensive margin (how many people experience the proposed mechanism) are large and inclusive and changes and change at the same time as the crime decline.  I add a sentence for the mechanisms that aren’t obvious, but each is worthy of a book-length treatment.  Graduate students: all of these are testable hypotheses.  Have at it.

As an appetite whetter from this second piece, consider how the list of 25 explanations closes:

20.  Widespread use of medication (Ritalin, anti-anxiety, anti-psychotic, anti-depressant)

21.  In-home entertainment (internet, video games, pornography, cable)

22.  Under-reporting as crime moves online

23.  Less cash in circulation

24.  Obesity and disability

25.  Air conditioning.

February 21, 2021 at 05:41 PM | Permalink


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