Moving the Needle on Evidence-Based Policing

Moving the Needle on Evidence-Based Policing

Written By: iacpblog

Blog Post

By Jason Potts, Lieutenant, City of Vallejo Police Department

We can’t know if something works or not if we don’t test it. Yet many police departments keep policies and practices in place simply because that’s the way things have always been done. Law enforcement is deeply entrenched in tradition, but when it comes to work as high-stakes as policing, we need to substantiate what we’re doing with evidence. Pure dogma and tradition are not enough.

I have been thinking about data, research, and evidence as they apply to policing for the majority of my 17-year career, but it was really three years ago when I turned to evidence-based policing. In 2015, I became a Law Enforcement Advancing Data and Science (LEADS) Scholar—a National Institute of Justice program that works with mid-career law enforcement to encourage the adoption of data and research to inform law enforcement policies and practices. The LEADS Scholars program has been a way for me to meet like-minded people who are equally passionate about using evidence to inform our work in law enforcement and has sparked a lot of the evidence-based projects I’ve done.

ALPR Technology to Combat Auto Theft

The City of Vallejo, California, where I work, has one of the highest rates of auto theft for a city its size, with a population of about 120,000 people. Inspired by the LEADS program, in 2017 I began a research partnership with BetaGov, a nonprofit research organization that supports research projects that have on-the-ground impact. With BetaGov, I examined the effectiveness of automatic license plate readers (ALPR), with the goal to understand whether ALPR technology works as effectively as we thought. Specifically, I was interested in whether using ALPR technology can increase stolen vehicle recovery, affect officer behavior, and improve the ability of officers to detect stolen vehicles. At the end of the trial, our data confirmed that ALPR technology led to higher frequencies of vehicle recoveries and arrests.

The power of this project is its ability to be replicated, and the on-the-ground application of its results. This was not an out-of-reach, theory-heavy academic research project. The randomized control experiment I designed with BetaGov is simple and could easily be replicated in other departments. If this research can be accomplished in Vallejo—where we are short-staffed, face budget constraints, and have high levels of violence—anyone can do it. The larger the problems a department faces, the more helpful evidence-based research results will be. In Vallejo, we took on this project knowing that ALPR technology could potentially allow us to be more efficient in identifying automobiles linked to crimes and individuals who commit those crimes.

Progress Necessitates Change

I joke that police officers dislike two things: change and the way things are. Progress necessitates change, but change is always difficult, particularly in a field as rooted in tradition as policing. In pushing for officers and departments to embrace evidence-based policing, I’ve met everything from enthusiasm to disinterest to disdain. There’s a lot of vulnerability when fighting for evidence-based ideas that question entrenched police culture and tradition.

Starting out, my research was met with support from my Chief, but a general lack of interest. Over the years, interest has picked up. Recently, I started to receive the help and support of a crime analyst in the department. Running rigorous research projects such as randomized controlled trials and other evidence-based programs can be difficult, but at the end of the day, we hope these studies will yield results that will help us become more efficient and effective as a department.

As difficult as it can be to promote evidence-based policing, we’re not doing it alone. In early 2016, I joined the American Society of Evidence-Based Policing (ASEBP) as a co-founder, with the goal of encouraging the national movement towards evidence-based policing. It’s been a difficult road, but well worth it. ASEBP held its first conference in May 2017, has grown to more than 100 members, and our members have presented on the Society at multiple conferences, including the IACP Annual Conference in Philadelphia, PA in October 2017. I’m proud of the work we have done, and hope ASEBP will continue to be a platform to move the conversation forward on evidence-based policing.

We’re seeing the needle slowly start to turn towards evidence-based policing, but the vast majority of policies and practices in U.S. police departments are still due to dogma, rather than data. As a profession, policing continues to evolve, but we have a long way to go. The medical field has come a long way from using bloodletting and leeches to cure ailments, but across any field, change is a slow and difficult process. Policing is still in its infancy for data evaluation, science, and research. My hope is that we can continue to shift our thinking from doing things the way they have always been done to evaluating the data in context while consistently looking for causality and evidence.

For more information on the Center for Police Research and Policy, please visit

Blog Post


Please sign in to read and get access to more member only content.



IACP - Loader Animation IACP - Loader Animation IACP - Loader Animation