Evidence-Based Policing Matrix
Individuals – Fox et al. (2022)
Study Reference:
Location in the Matrix; Methodological Rigor; Outcome:
Individuals; Focused; Proactive; Moderately Rigorous; Effective
What police practice or strategy was examined?
This study evaluated a strategy adopted as part of Project Safe Neighborhoods (PSN), an evidence-based federal-local initiative aimed at reducing violence and gun crime, identifying prolific violent offenders, and deterring or incapacitating them from offending. The Tampa Police Department (TPD) developed a new strategy that combined the PSN practices of increased enforcement and sanctions to deter prolific offenders with a new risk assessment called the Violent Impact Player List (VIP List) to more effectively identify prolific violent and firearm offenders that were subject to the PSN intervention. The VIP List drew upon evidence-based risk factors weighted to reflect the behaviors most predictive of future violence and firearms. Specifically, TPD’s Violent Crime Bureau and partnering federal agencies aimed to increase the certainty of arrest by allocating resources to collaborative proactive investigations and enhanced enforcement for serious crimes currently committed by VIPs and advertising this change in policy through the news and officer communications with the VIPs. Additionally, TPD worked closely with the U.S. Attorney’s Office (USAO), State Attorney’s Office (SAO), and Public Defender’s Office in Tampa to increase the severity and certainty of punishment when VIPs chose to re-offend.
How was the intervention evaluated?
A quasi-experimental design was used to evaluate the impact of the PSN initiative on violence and gun crime in Tampa over a 6-year (3 pre-implementation, 3 post-implementation) period. Monthly trends in Tampa during this time were compared to those in six other jurisdictions which were selected based upon their similarity to Tampa on several factors, including geographic proximity (all in central Florida), agency location (touristic, coastal), population size, total police officers, total index crimes, violent crimes, gun crimes, and total violent crime arrests. The pre-test period covered the 3 years between January 1, 2013 and December 31, 2015. The start date of the PSN intervention was January 1, 2016, and the follow-up period included the 3 years through December 31, 2018. The authors used the synthetic control method (SCM) to weight the data from the comparison localities based on their similarity to Tampa, thus providing a better approximation of what would have occurred in Tampa had it not received the PSN program. Moreover, they conducted a series of analyses (using conditional zero-truncated negative binomial regressions) to examine the duration of PSN effects on violence and gun crime.
What were the key findings?
Results indicated that PSN was associated with a 24.4% reduction in violence and a 24.0% reduction in gun crime rates in Tampa. The comparison localities showed much smaller decreases in violence and gun crime over the same time period (as measured by the weighted comparison series). The effects of PSN on violent crime diminished over the 3-year follow-up, but the effects on gun crime remained relatively constant.
What were the implications for law enforcement?
The authors suggest that the use of the VIP list to identify prolific offenders subject to the PSN intervention yields a notable effect on violence and gun crime reduction. Furthermore, this approach was associated with substantial decreases in violence and gun crime over the 3-year follow-up period, but importantly, total arrests in the treatment jurisdiction also decreased. This has potential positive effects on police-community relations and perceptions of police legitimacy and effectiveness. In other words, it appeared that TPD targeted a small group of people at risk of committing the highest number of violent and firearms crimes and then successfully deterred or incapacitated them from committing future offenses. Lastly, the program was estimated to have prevented more than 250 violent and gun victimizations.
Where can I find more information about this intervention, similar types of intervention, or related studies?