We met with Director of the Jerry Lee Centre for Experimental Criminology and Wolfson Professor of Criminology Emeritus at the University of Cambridge, Dr. Lawrence Sherman, to talk about Big Data analysis and tracking in policing, evidence-based policing, the “defund the police” movement, and so much more. Enjoy!
"I think a good experiment in terms of what happens if you have an elite faction of whatever protest group with the plan to say, "We can do something better than the police, so let's abolish it." But they didn't have the second part of the plan which is, "Well then what do we do?""” – Dr. Lawrence Sherman
Top criminologist Dr. Lawrence W. Sherman discusses hotspot mapping of crime concentrations and patterns, Big Data analysis and tracking in policing, the “defund the police” movement, and evidence-based policing. Director of the Jerry Lee Centre for Experimental Criminology and Wolfson Professor of Criminology Emeritus at the University of Cambridge, Dr. Sherman talks with Dr. Jed Macosko, academic director of AcademicInfluence.com and professor of physics at Wake Forest University.
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(Editor’s Note: The following transcript has been lightly edited to improve clarity.)
Jed Macosko: Hi, this is Dr. Jed Macosko at Academicinfluence.com in Wake Forest University, and today we have a very special guest coming to us from Cambridge University who’s a professor of Criminology. And so, I’d like to introduce Professor Sherman to you, and Professor Sherman, thanks for joining us today.
Can you tell us a little bit about your PhD advisor and what he was known for, and how was it that you pioneered the use of policing hot spots in both the United States and in other places?
Lawrence Sherman: I was very fortunate to have as my PhD advisor, Professor Albert J. Reese Jr, who was one of the foremost scholars of policing in the world in the 20th century. He developed a systematic observation approach of coding every encounter between police and citizens in 10,000 encounters in Boston, Washington and Chicago, and noted the strategic differences between what happens when the police initiate the contact and when the police are invited into the situation involving sometimes a crime, sometimes a dispute. He gave us so many insights.
But one of which was, part of the engagement in the 1980s with the National Institute of Justice, by which time I was teaching at the University of Maryland and we were going to various meetings. There was a lot of concentration on repeat offenders and the concentration under what’s called sometimes the Pareto curve or a power curve, where instead of having a normal distribution you’d have the hockey stick.
And the hockey stick is that, at the far end of the distribution, you might have 5% producing 80% of what’s going on in the distribution, whether it’s 5% of the criminals committing 80% of the crime or more plausibly, 80% of the harm from crime, and I’ll come back to crime harm ’cause it’s particularly important work that we’re doing at the moment.
But what Al Reese said to me was, “You know that concentration among offenders, that’s probably true of places.” And there were some preliminary findings with specific types of offense like burglaries or domestic violence that some folks in Boston, Glen Pearson and his colleagues had been working on.
What I was able to do with my mentor, Tony Bouza, who was by then the chief of police in Minneapolis, was to take over 300,000 calls in one city in one year and distribute them by addresses. And we discovered that 3% of the addresses produced 64% of the calls, which was just this incredible concentration.
And every test of the distribution of either calls for service or reported crime, or even more so, the harm from crime, every test since then has pretty much shown the same concentrations subject to some methodological tweaks like whether you’re looking at addresses or the entire street block between two corners, or even areas that are designed through geometric patterns, which seems now to be an exciting new way to distribute crime events across a city or even traffic accidents.
And Al Reese, I think, was very important in my life because he did what Einstein said is the most important thing in science, which was he asked the right question.
And then Einstein went on because he was… Einstein was good at asking questions and not very much of an experimentalist, not at all experimentalist. He said, “Mirroring experimental skill, anybody can have that, but asking the right question.” So that’s what Al did. And I went out and my colleagues went out, and we kept looking at the data, and we kept finding the same thing.
But what I would say is more important about that, and not something that Al taught me as much as Tony Bouza, the Spanish-born police chief in Minneapolis for nine years who was hailed for creating a crime lab at the end of his successful administration as a much beloved police chief, what Tony Bouza said was, “The research won’t matter if we don’t put it into practice.” And so Tony Bouza helped us to do experiments, randomized trials with 110 high crime locations, 55 of which got twice as much patrol as the other 55, and we showed substantial reductions in total crime, robbery was cut in half.
And even more important, we were able to see with Chris Koper’s analysis that whenever the police left a location, they had more of a deterrent effect residue, the residual deterrence was longer if they’d stayed at least 15 minutes as opposed to staying a minute or two and then leaving.
So Chris Koper’s Koper Curve got us thinking about what is the nature of general deterrence scientifically and experimentally, and not just the kind of theory that Jeremy Bentham developed with Sir Robert Peel in founding the Metropolitan Police in London in 1829. We were finally putting the science on it with as much help if not moreso I would say, from Tony Bouza than from any of the academic criminologists that we were working with. So much thanks to Tony who’s in his 90s and still living in Minneapolis, and I hope will see this interview.
Jed: I hope so too. Well that is fascinating that you were able to really take something, sort of an off-hand comment that your PhD advisor mentioned and really run with it. We are also talking with Professor Weisburd who also has been attributed to this hot spots policing.
Can you explain any relation between you and Weisburd’s theories and how they got implemented?
Lawrence: Well, I can start out by telling you that both David and I had outreach as PhD supervisor, so if we think in terms of academic families, David and I are brothers. And he actually invited me to be a visiting professor at Rutgers University shortly after I had discovered this concentration across every address in Minneapolis.
And we got to talking about a previous patrol experiment in Kansas City led by George Kelling, which had big areas, and most of those areas didn’t have any crime. And it didn’t really show any difference, how much it actually disproved any difference in having more patrol versus less patrol is still a matter of dispute, but David and I sat together in the office at Rutgers and designed the hot spots experiment that Tony Bouza let us undertake.
"…I think that's because we have to educate them more and have them understand the science just in the way that we sometimes have to do with doctors who still don't wash their hands even though they don't challenge the science about preventing infection by handwashing, they just kind of can't be bothered, and so they don't wash their hands."” – Dr. Lawrence Sherman
So we proceeded to complete and publish, with the support of the National Institute of Justice, the first randomized trial in hot spots policing. There are now almost 80 of those randomized trials or close to quasi-experiments that have consistently found support that it matters that police go where they are directed by big data analysis rather than just driving any place they feel like it.
And it’s still contentious because nobody likes to have their freedom restricted and if you tell a constable or a patrol officer in the United States, “It’s really important that you go to these three locations tonight and stay there for at least 15 minutes,” they’re not inclined to agree.
But I think that’s because we have to educate them more and have them understand the science just in the way that we sometimes have to do with doctors who still don’t wash their hands even though they don’t challenge the science about preventing infection by handwashing, they just kind of can’t be bothered, and so they don’t wash their hands.
And that comes down to why I developed this thing called the three Ts, which will be very different from… David’s work is superb in looking at the targeting and the testing of these crime distributions, and a lot of my work in the last 10 years has been focused on the third T, not just the targeting, not just the testing, but the tracking. And how do we track what police are doing just like how do we track whether doctors are washing their hands?
We can get big improvements if we can make the tracking matter and change the culture of policing or medicine around the idea of greater compliance with the best practice on a case-by-case basis driven by a system that is constantly measuring its success in producing the best practice most of the time.
Jed: Well, now you’re touching on an analogy to medicine that I can really relate to. A lot of doctors that I’ve spoken with feel that these metrics that make sure they’re compliant with different things are coming from the top-down, coming from administrators who aren’t doctors, and in many ways, they’ve sort of felt like their profession has gotten away from them. They no longer control the medical profession as doctors, it’s being run by administrators and people who also make a lot of money at the very top, CEOs of medical companies like that.
Is there the same feeling that the metrics that you’re sort of forcing on police officers or coming from the top-down, and they don’t like it, and they feel like they’ve lost control of their profession, or have you managed to avoid that trap that some doctors feel?
Lawrence: Well, I think in a way, it’d be a good problem to have because so far, the police chiefs around the world have not chosen to adopt rigorous tracking regimes.
But at the ground-level, you find some inspectors who are meeting with their officers, looking them in the eye, talking face-to-face about whether they’re doing what they were asked to do, and we have research now that shows that when the ground-level leadership in policing treats the officers with respect, with dignity and most importantly, with compassion and commitment to this being an important job, and giving it some meaning in the context of this neighborhood or this railroad station where one of the studies was done, then the potential for this being a bottom-up grassroots movement, it is huge.
And I have to say, unlike the Police Chiefs’ Associations, the Societies for Evidence-Based Policing are primarily membership groups of constables and detectives and sergeants, and some inspectors, some of whom will go on, like Alex Murray who’s the commander of the Metropolitan Police, but who started the first Society for Evidence-Based Policing when he was an inspector.
"You can't expect people to buy into something they don't understand."” – Dr. Lawrence Sherman
So ironically, you could say this is something of a middle-management professional revolution within policing rather than being top-down in the sense that, the officers who are doing this want to do the best they can, and they wanna do a better job for the sake of doing a better job.
And it’s very important to see the difference between that and having a top-down order from people who don’t even explain why there should be more patrol in some locations than others when there’s a massive difference in the risk of violence to citizens that can be prevented by the officers doing just that.
But if you don’t bother to explain it to people, if you don’t have discussion groups or training sessions or even an educational training curriculum for the police that talks about crime prevention, and that’s largely lacking from police training. You can’t expect people to buy into something they don’t understand. So that’s why so much of what we’re doing now is to try to stimulate intellectual excitement among practicing police officers about the application of the latest science that we can tell them about.
Jed: That is great. I really have a lot of hope now. I mean some people would argue that this is the darkest hour of policing, that police have lost the trust of the communities. What you’re saying sounds so hopeful that there’s this grassroot movement that can really take hold.
Revolution, you mentioned, so which way should we feel about it? Are we at the cusp of something great? Or we are at the precipice of a giant pit we’re falling into.
Lawrence: I think that we are falling away from the pit of, defund the police, abolish the police, if only because in places like Minneapolis where a majority of the City Council pledged to abolish the Minneapolis Police Department, the pushback from minority neighborhoods where gun violence started to soar and other problems developed, just as the New Yorker magazine quoted some of the leaders in those communities to saying, “We don’t wanna defund the police, because if the police aren’t around, we’re gonna have a lot worse people pushing everybody around in the community.”
And the failure of the Minneapolis Police initiative to abolish the police department is, I think, a good experiment in terms of what happens if you have an elite faction of whatever protest group with the plan to say, “We can do something better than the police, so let’s abolish it.” But they didn’t have the second part of the plan, which is, well, then what do we do?
"It's kind of like having an airplane flying without a pilot, just because you wanna replace the pilot, you kinda make sure there's a co-pilot sitting there, while you're doing that."” – Dr. Lawrence Sherman
And over 20 years ago, I wrote a piece saying, there are some police departments that should be replaced, but you wanna have an orderly replacement process so that at no point is there a city without a police service. It’s kind of like having an airplane flying without a pilot, just because you wanna replace the pilot, you kinda make sure there’s a co-pilot sitting there, while you’re doing that.
And that’s what happened in Camden, New Jersey, where the state legislature abolished the city police, but it had the county police force all ready to take over on the day that the city police force was abolished, and that’s been a very successful effort, and I have lots of hope coming out of the Camden experience that that can happen elsewhere in the United States. I’ll have to say that police legitimacy around the world has suffered because of the killing of George Floyd and many other very unfortunate incidents in the United States.
"…I think the optimism in this country for evidence-based policing, making a more profound influence on police practice, is greater now than it's ever been."” – Dr. Lawrence Sherman
And this weekend with the Nigerian police possibly killing up to 50 people who were simply protesting police brutality, we can see this as as a global crisis with global causes, but in places like the UK, Sweden, Denmark, where we have a lot of students, I think the potential for changing the way they make decisions, changing the way they think about something that’s very deep and police values in Britain, which is proportionality and not using the kind of force that the Supreme Court of the United States has allowed the police to use, to shoot people who won’t drop their knives.
You can’t do that in England and in that legal context, much greater respect for limiting the damage that the police do as a matter of law in this country, it sets the stage for using research in ways that make it much more similar to medicine and for the last 200 years, the British police model has been a shining example to the rest of the English-speaking world and indeed many other parts of the democratic world, and I think the optimism in this country for evidence-based policing, making a more profound influence on police practice, is greater now than it’s ever been.
Jed: That is extremely helpful. And in these times, I think that that’s something we can really cling on to as we try to re-formulate how we do policing in the United States and beyond. So thank you so much, Professor Sherman, for spending some time with us today, helping us to understand what’s going on. We really appreciate it.
Lawrence: Thank you, Jed.
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