Hot Spot Policing: Using Evidence To Reduce Crime

July 17, 2024

In the 1970’s David Weisburd was a freshly minted criminologist when he was invited to join a police research project.

For one year he followed two police officers as they patrolled the streets of a suburb of Brooklyn.

David’s job was to watch, take notes on what he saw and write a report.

It wasn’t long before David noticed something odd.

“What I found was, quite quickly, that after we got to know the area, we spent all our time on one or two streets, it was the bad neighborhood of town, [but] most of the streets didn’t have any crime.”

When the year was up, David teamed up with Larry Sherman, another young criminologist. They wanted data to check their observations.

But getting data was harder than it sounds. When the police were told about a crime, they recorded what suburb it happened in. But that was far too broad, they needed to know what street.

Luckily, Larry knew a police chief in Minneapolis who could help.

When they got their hands on the data and started analysing it, they were shocked.

3.3% of the streets were responsible for 50% of the crime

David’s observations were correct. Crime was extremely concentrated.

They checked other cities:

  • New York.

  • Seattle.

  • Cincinnati

  • Kansas City

  • Dallas.

  • Even in Tel Aviv.

They found the same pattern. In city after city, a lot of the crime occurred in a small number of the streets.

This idea influenced how we think about crime and policing.

“Like most other people, my studies were about people. I said, maybe we ought to be more concerned with places.”

David Weisburd

This was an important idea because once you know where most crime happens, you can focus your resources on those areas.

This idea would be called Hot Spot Policing.

Below is an example of a hot spots map. It shows a portion of Seattle. The different colours tell us something about the rate of crime, red and orange mean lots of crime.

As you can see, most of the crime is happening in only a few streets

Example of a Hot Spots Map in Seattle

And wonderfully, evidence suggests hot spot policing does reduce crime.

One study in Dallas found that when police focused their attention on the city’s hot spots, violent crime fell by 11%. Importantly, crime rates didn’t meaningfully change in other areas. So it’s unlikely that people spotted police officers and just wandered over a few streets to commit the crime.

Hot spot policing was at the start of an era called Evidence-Based Policing.

The idea is simple and powerful. Use evidence to help us understand crime and ways of preventing it.

As the late great psychologist Amos Tversky liked to say: “Always keep one hand firmly on data”

Cheers,

Jared