PLI Podcast: Zimring on Crime Drops, Metrics and Midnight Basketball

Posted on 20 April 2011 by


This week on the Police-Led Intelligence Podcast, we speak with Professor Franklin E Zimring, author of The Great American Crime Decline and (as we wrote a couple of weeks ago), the forthcoming 38-page journal article and book on New York City’s remarkable and sustained drop in crime rates since the 1990s, to be entitled: The City That Became Safe: What New York Teaches About Crime and Its Control.

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Frank and I started speaking by phone when I mentioned that I loved the metric of reduced prisoners providing the money to pay for extra cops on the street, and we asked him to join us on the podcast to talk about his work, that metric and others. By the way, during the podcast, I credit Zimring with creating a way of looking at a particular gun statistic which was in fact created by Philip J Cook, and Zimring credited me with referring to these kinds of statistics as metrics. So there.

According to Frank, what New York City did reducing its crime rate was twice as big and lasted twice as long as the average American city. While he couldn’t state what caused the crime decline everywhere else, he felt he could take a stab at the New York difference. There wasn’t a major population change, not an economic change specific to New York, not to the culture, the schools didn’t get wonderful, economic inequality didn’t leave.

Zimring instead credits extraordinary changes in policing: more cops, more aggressive patrol, substantially changed tactics, and, for at least three crimes – auto theft, burglary and robbery – these changes made a tremendous impact.

The theory of crime we were working with until the 1990s was that crime was a persistent, predictable feature of high-rate offenders, and you either lock them up or they continue to offend.

That theory meant that police were not preventively effective – that is, if you send ten cops to 125th St and 8th Ave, the crooks will go to 137th and 8th Ave. They’ll simply move.

We now know, Zimring says, a combination of hotspots policing and the destruction of public drug markets, and maybe COMPSTAT mapping, and maybe gun programs, drove annual crime rates way down. That must mean that the theory of crime we were using was just wrong: if you send a lot of cops to 125th St and 8th Ave and there are robberies and burglaries not committed there, it turns out that the intention to commit them is circumstantial and contingent enough so that crimes that don’t happen on that block probably don’t happen at all in the city.

These “temporary palliatives” turn out to also be a part of long term prevention.

What they have in New York City that got Zimring’s attention is a relatively stable population, in three of the four major boroughs we have the same overall population in virtualy the same economic circumstances, and no more or them locked up than were locked up 20 years ago – indeed a few fewer. And we have 80% fewer homicides, robberies and burglaries, and the auto theft rate in New York City in 2009 was seven per cent of what it had been in 1990.

Where have the criminals gone?
They’ve gone nowhere. They’re simply offending less. This is a game-changing window into the nature of crime in the US.

We started speaking about Zimring’s work when, as I said, he brought up a very non-obvious relationship between some seemingly unrelated things – prisoner population and funding for police on the streets. I asked about a metric that Zimring had given me during a phone conversation, in which residential gun ownership was inferred from the level of suicide by handgun as a percentage of total suicides in different cities.  Zimring mentioned that from that it was quite easy to tell that New York City had a far lower residential handgun ownership level than that of Houston, TX.

I asked him about this and other non-obvious data gathering. Frank rightly credits the suicide metric to Phillip J Cook and says that the reason it’s so brilliant is that it examines readily available vital statistics for sources of insight and it looks at the group ultimately at risk – with suicide by handgun, researchers found readily available statistics that referred to an entirely different at-risk population from that of those who commit street crimes. It’s much older group of males than street hoodlums, spread across social and cultural groups.

Household Gun Ownership in NYC
Tying this to New York, Zimring points out that what was different from 1985 to 1990 was a strange contrast – household gun ownership in NYC was quite low. New York City’s counties were all near the very bottom of the percentage of total suicide by handgun, nationally. So a burglar hitting an apartment in New York stood a pretty low chance of scoring a handgun.

But when it came to New York City homicide, the percentage of handgun use in 1990 homicides – 75% – was very high compared to other areas. This says that there is a relatively thin layer of guns on the street, and he points to further research that says that, once a gun is carried on the streets of New York, it doesn’t take long to get in trouble. It’s not a question of guns being carried for years – but rather, for months and sometimes weeks before they are involved in a crime.

This was good and bad news for the City. The bad news was that there were enough guns on the street to result in violent episodes – assaults and robberies gone wrong were highly lethal because guns were used. But the good news was that, if you could confiscate street guns you can make a positive difference in making the city safer – the difference between New York and, say, Houston is that if you confiscate guns from the street, it’s a heck of a lot harder for criminals to get another one by walking down the street or breaking into a house.

Does This Translate to Other Parts of the Country?
This all came up because we were discussing to what extent this great news from New York City could be generalized to other cities. Many things make crime prevention easier in New York City than in other large cities – starting with its high population density. Compared to Los Angeles, there are four times as many citizens per square mile. This means one cop can see a lot more citizens.

Zimring claims that the extraordinary similarities between New York City and its sister big cities with high rates of crime outweigh the differences.

There is, he says, no evidence that the situational and contingent nature of crime in New York City – which makes it possible that when you prevent a robbery on 125th St the robbery rate goes down – is not true for cities around the country. This suggests that a whole series of what we used to consider temporary fixes can work better and longer than we had supposed. He’s saying that it’s not that the policing tactics or programs or what have you that export to the rest of the country, it’s that crime is the same around the country.

This gets harder when talking about rural settings. One thing that makes policing in cities easier in the new police strategies is the way crime is concentrated and easy to find. Crime mapping works because you have hotspots in which you can expect crime to occur. Zimring’s not sure that when you get outside intense concentrations of urban crime, that you have the same metrics operating.

On the other hand, by the time you’ve left the big cities, you’ve left two thirds of the American homicide rate behind.

Prisoners v Cops on the Street
The reason we’d asked Frank on the podcast was the first metric that we wrote about was that New York City reduced crime by 80% without a corresponding increase in secure confinement. The primary means, almost the exclusive means, of deterrent in the United States has been prison. In 1973, Zimring says, there were 203,000 people in prision in the US and another 400,000 in jail. We now have 1.6 million – eight times as many – people in prison.

In New York city, throghout the major crime decline he writes about, Zimring says that there was never a huge increase in incarceration as in the rest of the country. The peak confinement rate was in 1996 or 1997, when the total was up 11%. Then it turned around; by 2009, when you had the 82% homicide and 84% robbery drop, there were 28% fewer people locked up than had been locked up in 1990. Had the population changed? No. Where were the criminals?

When they returned from prison and jail the probability of their offending in the future went way down. Following releases of people from New York City prison system at its peak in 1990, a prisoner released had a 28% likelihood of being convivted of felony in next 3 years. Seventeen years later, he had a ten per cent probability.

Police didn’t get terribly inefficient – the reason this rate dropped 64% was that the crime rates of people we had already identified as active offenders was reduced by 64%.

Criminals Aren’t All That Predictable
What we know, Zimring says, is that crime isn’t as predictable and persistent even in the high rate offenders. That becomes another good news/bad news story. It’s bad news for the most prominent crime control technology: imprisonment. It turns out to be vastly less cost effective than everything else you would do – aggressive patrol, hotspots policing, midnight basketball games – which is banking on people being changable.

If they followed the national trend, right now the 46,000 people in prison/jail in New York City would be increased by 58,000 – more than double. At a conservative $25,000 per year cost per prisoner (and they really cost more) that would still be $1.5 billion. So Zimring reckons that 58,000 fewer prisoners locked up more than pays for every extra police officer in New York City twice over.

These programs work, he says, not because people are getting sentimental about locking people up, but simply because the nature of crime is a lot less predictable, and is more preventable, than we ever thought.