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Notes From the Field: Using Evidence-Based Policing To Combat Violent Crime

Notes From the Field
Date Published
February 27, 2020

In March 2012, a police officer was shot in the line of duty here in Manchester, New Hampshire. A convicted felon on federal probation shot at the officer repeatedly during a foot pursuit — resulting in wounds that nearly took the officer’s life. 

That officer, Dan Doherty, is a good friend of mine and was an academy classmate. Thankfully, he survived, but the ordeal shook the department, the community, and me personally. 

The event seemed like the result of an increasing pattern of gun crime in our city, and it became influential in my passion for violent crime reduction and evidence-based policing. Many of those involved in evidence-based policing can trace their interest in the subject to a poignant moment that had a drastic impact on them. From those incidents, many begin searching for what really works in policing. My efforts in violent crime reduction followed this path.

After Officer Doherty was shot, I began paying closer attention to the data surrounding gun crime in Manchester. This adherence to data to inform and drive strategy was the first step in implementing evidence-based practices. The data showed that 2012 — the year Officer Doherty was shot — actually had the lowest number of incidents in the recent past.

However, in 2013, Manchester saw an 82% increase in gun crime from the previous year — 158 incidents in 2013 compared to 87 in 2012. Gun crime in 2014 continued its upward trend, with 161 total incidents by year end. These numbers, for such a small city, were alarming and, as a police officer, I was offended. To me, the level of crime, and specifically of gun crime, was the result of ineffective policing. Understanding this problem, I turned to research to find a solution.

Identifying Crime Patterns

Like many police officers, I had completed an undergraduate degree in criminal justice prior to getting hired. While on the job, I completed a master’s degree in criminal justice, expanding my knowledge of criminological theory and research. 

As I began diving into the literature regarding violent crime and policing strategy, I recognized that I had the opportunity to translate the hard work I had done in my undergraduate and graduate programs into application on the street. A logical place to start was my interest in environmental criminology and place-based crime. With an understanding of the research, I returned to the data to see if gun crime in Manchester had a relationship with place. I also began to look further into the drivers of gun crime and any other patterns that a more rigorous examination could glean. 

Not surprisingly, I came to two main conclusions: first, that gun crime did cluster in certain small micro areas and second, that much of the increase in gun crime was due to neighborhood gang activity. Using the evidence base of hot spots policing and focused deterrence, Manchester Police utilized grant funding in 2015 to provide focused patrols in the gun crime hot spots. We also conducted focused deterrence-like activities, such as home visit “knock and talks” of individuals heavily involved in gang violence.

Anecdotally, the efforts seemed to be a success. Gun crime dropped by 16.7%, from 161 incidents in 2014 to 134 incidents in 2015. While this could have been seen as a regression to the mean, the following year (when these efforts were not in place), gun crime surpassed pre-intervention levels, increasing 26.8% to a record level of incidents. 

Unfortunately, we did not conduct rigorous evaluations of our efforts. The initiative did not include a sound experimental design, nor were there identified control areas to compare against. Nevertheless, the use of evidence-based policing strategy was a step in the right direction and a continuation of adopting evidence-based practice as a standard of strategy development.

Support From Project Safe Neighborhoods

The difficult year of 2016 and a continued high level of gun crime in 2017 brought Manchester Police back to the drawing board in looking for ways to reduce gun crime in the city. Using the Bureau of Justice Assistance’s Project Safe Neighborhoods (PSN) as a catalyst, Manchester Police and partners from New Hampshire State Police and New Hampshire Probation and Parole used evidence-based policing strategies as the foundation of a competitive grant application. 

Fortunately, the PSN grant was awarded to the city and partners began collaborating to reinvigorate the place-based approaches that had been successful in 2015. The PSN initiative involves a research partner from a local university, which strengthened our use of evidence-based practice in the strategy. With this support, we identified control areas to measure against and the dates and times of the deployment of these additional resources were randomized. 

The initiative was implemented for a 14-month period from August 2018 through September 30, 2019. Manchester Police worked to deploy additional officers to gun crime hot spots – a placed-based approach to crime reduction — in conjunction with home visits of individuals on probation or parole who resided in those areas — a person-based approach.

The rigor of our method was much stronger than our initial efforts in 2015, and it was another step in the right direction to incorporate evidence-based policing into the department. However, the implementation came with a few challenges.

Issues arose with political pressures to further increase patrols when gun crime spikes occurred during the evaluation period. This inhibited the efficacy of the control areas and the overall efforts of the strategy. Another challenge was the officers’ adherence to only patrol the identified hot spots.

Results are still being evaluated, but the initial indications are that hot spots that received the intervention saw gun crimes decrease by 42.1% (19 gun crimes during pre-intervention versus 11 during the intervention) whereas the comparison areas saw a 100% increase in gun crime (six during pre-intervention versus 12 during the intervention).   

Overall, gun crime citywide showed an increase of about 3% post-intervention. Nevertheless, the lessons learned from this attempt at evidence-based practice are helping to shape the efforts of future strategy.

Further Analysis

A full analysis of the 2017 PSN grant award is in progress, and initial examination indicates we missed the mark in our person-based approach. A large number of the gun crimes and shootings were the result of continued gang conflict that spiked numerous times during the intervention period. While the efforts didn’t have the results that were expected, it is important to understand the shortcomings so that more effective interventions can be used in the future.

As we move into 2020 and beyond, Manchester Police will continue to use evidence-based principles to influence its violent crime reduction strategy. The hot spots policing strategy will continue, with an emphasis toward fidelity of the patrols. Using lessons learned from the previous interventions, we will focus the person-based strategy to better identify those closest to gun crime and provide more evidence-based interventions. Through stronger planning, intervention methodology, and a continued adherence to measurable data, it is the hope that the city will achieve greater impacts on violent crime.

The journey toward infusing evidence-based policy into a department is not just a matter of “flipping a switch.” There are challenges in every effort, but persistence and learning from the past are necessary for policing to progress into an evidence-based profession. 

Experience has shown that it is vital to use data and analysis to identify problems, develop strategy that is rooted in evidence-based policing, and ensure the response is focused on the problem and is well- balanced. 

Lastly, efforts must be measurable and results need to further inform future strategy and policy. Evidence-based policing is achievable by all police agencies and, as a profession, we must demand it to ensure we are providing the best service to our communities.

About Notes From the Field

The National Institute of Justice (NIJ) is the research, development, and evaluation arm of the U.S. Department of Justice. NIJ aims to address the critical questions of the criminal justice field, particularly at the state and local levels.

NIJ Director David Muhlhausen developed the Notes From the Field series to allow leading voices in the field to share their strategies for responding to the most pressing issues on America’s streets today.

Notes From the Field is not a research-based publication. Instead, it presents lessons learned by on-the-ground criminal justice leaders, from years of experience and thinking deeply about criminal justice issues.

Date Published: February 27, 2020