Do police really stop crime and violence?

Do police really stop crime and violence?

By German Lopez

 

This week, I’m looking at the strong evidence that police really reduce crime and violence, along with new research looking at the effects of a fraudulent 1998 study that linked vaccines to autism.

 

Thanks for reading! If you have any questions or comments, email me at german@vox.com or find me on Twitter at @germanrlopez. And if you want to recommend this newsletter to your friends and family, tell them to sign up at vox.com/weeds-newsletter.

EXPLAINED IN 600 WORDS

There’s good evidence for policing

The US is seeing a spike in homicides, with the murder rate rising by an estimated 25 percent in 2020 and by 12 percent in large cities so far in 2021. In confronting this problem, some progressives — galvanized by the “defund the police” movement — have argued that the response shouldn’t center around, or even involve, the police.

 

But there is good evidence that more policing would help turn around the murder spike.

 

There’s a wide range of evidence showing that more cops lead to less crime and violence. A recent study, published by the National Bureau of Economic Research, concluded, “Each additional police officer abates approximately 0.1 homicides. In per capita terms, effects are twice as large for Black versus white victims.”

 

Concerns about shootings and violence caused by police themselves might make some places reluctant to put more police on the streets. But there is good evidence for specific, nonpunitive policing strategies that cities could adopt.

 

Hot spot policing, for example, focuses on problem areas — as small as specific blocks — in a community. Officers are deployed to deter and prevent further crime and disorder. They don’t have to engage in heavy-handed actions (like mass arrests or stop-and-frisk); they can act as surveillance, based on the principle that almost no one is going to commit a crime in front of a cop.

 

A 2019 meta-analysis of dozens of studies from the Journal of Experimental Criminology found that the approach works, reducing crime without displacing it to neighboring areas.

 

Another strategy, problem-oriented policing, homes in on a specific problem in a community — for example, shootings — and brings together the police and other community resources to comprehensively address it. A 2020 review of the evidence from the Campbell Collaboration found the approach worked, estimating it led to 34 percent less crime and disorder compared to control groups.

 

There’s also weaker evidence for what’s known as focused deterrence. With this approach, police and community leaders collaborate to send a clear message, through one-on-one or broader meetings, to people known to be involved in violence: You either stop, with help and resources from the community, or you will face penalties.

 

A 2019 review of the evidence from the Campbell Collaboration found studies on focused deterrence have been largely positive. But unlike hot spot policing and problem-oriented policing, none of the big studies on focused deterrence are randomized controlled trials — making it hard to say with confidence that the approach works.

 

What about the alternatives to police? One popular idea is deploying violence interrupters, people with a history in their communities and typically crime and violence who can act as trusted messengers to de-escalate conflicts before they turn violent. But a 2020 evidence review from the John Jay College of Criminal Justice found that the studies for violence interrupters are “mixed.” (More on that research in a Vox explainer.)

 

Other alternatives, from summer job programs to greening vacant lots, have stronger evidence behind them. But these programs tend to take a longer view of crime; they focus on root causes, like economic hardship and neglect, that take a while to heal. 

 

As Anna Harvey at New York University has told me, “At least as far as the research evidence goes, for short-term responses to increases in homicides, the evidence is strongest for the police-based solutions.”

 

One problem with the policing research is it almost never evaluates the full costs of policing. That’s not just the financial, but other problems too — like the damage of mass arrests, police killings, and so on. It’s concerns about those costs that have fueled protests and calls for alternatives.

 

But this is the evidence we have. So if the goal is to quickly address the past year’s spike in murders, the police will likely have to be part of the answer.

 

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PAPER OF THE WEEK

How a 1998 study empowered modern anti-vaxxers

A recent study published by PLOS ONE looked at the long-lasting effects of a fraudulent 1998 study that linked the measles-mumps-rubella vaccine to autism, finding that the misleading research seemed to lead to stronger anti-vaccine attitudes.

 

Researchers Matthew Motta and Dominik Stecula looked at how the 1998 study, which drew attention globally, affected both complaints to the national Vaccine Adverse Events Reporting System (VAERS) and press coverage by major television outlets and newspapers.

 

Sure enough, complaints to VAERS increased after the 1998 study.

 

A chart of complaints to VAERS.

And press coverage around vaccines, based on an automated sentiment analysis, also got more negative overall.

 

A chart of vaccine press coverage.

This is just one study, and more research is needed to validate the findings.

 

But it indicates the potential power of widely covered yet ultimately fraudulent research: It can stick around, shaping public opinion for years to come.

 

Given America’s current struggles with vaccinating people against Covid-19, the new research also raises questions about how much of the country’s current predicament is rooted in a foundation laid down by the 1998 study.