Evidence-Based Policing Matrix
Individuals – Ariel et al. (2019)
Ariel, B., Englefield, A., & Denley, J. (2019). I heard it through the grapevine: A randomized controlled trial on the direct and vicarious effect of preventative specific deterrence initiatives in criminal networks. The Journal of Criminal Law and Criminology, 109(4), 819–867.
Location in the Matrix; Methodological Rigor; Outcome:
Individuals*; Focused; Highly Proactive; Rigorous; Effective
*This intervention could also be considered a group-focused intervention, as described by the authors.
What police practice or strategy was examined?
The intervention tested was proactive engagement by police officers with prolific offenders. Prolific offenders were defined as having been arrested at least three times in the 48 months prior to the study, at least once in the last two years, and at least once for a Part I crime. Patrol sergeants were assigned to specific prolific offenders to ensure an officer under their command met with those individuals once during the experimental period. Officers were provided information about the individual’s involvement in the criminal justice system before meeting with the person in a field contact setting. Officers then conveyed to each individual both orally and with a pamphlet that the prolific offender was now under increased police scrutiny. Officers also provided the individual with a list of available resources that might help them stay away from criminal activity. While the intervention did not specifically target co-offenders or criminal associates, the idea was that these messages would be shared with them by the targeted individuals.
How was the intervention evaluated?
The specific deterrence intervention was evaluated using a randomized control trial in Sacramento, California. The researchers randomly assigned half of all prolific offenders known to police to the intervention. The researchers then measured arrests and charges for new offenses after the intervention was implemented for the targeted offenders, their co-offenders (people they offended with), the control individuals and their co-offenders, and the entire criminal social network to which they were associated.
What were the key findings?
In all comparisons, the treatment groups offended less than their control counterparts. Individuals who were warned, as well as their co-offenders and their entire criminal network to which they were associated, had lower rates of arrests and rates of new charges than those who did not receive the treatment (or their associated co-offenders and criminal networks).
What were the implications for law enforcement?
The authors argue that the findings provide evidence that targeted preventative deterrence by the police can not only reduce criminal behavior of prolific offenders, but also their co-offenders and their social networks more general. They also suggest given the likely variations in how officers deliver these messages, that policies of specific deterrence can lead to crime reductions, regardless of how these messages may be delivered.
Where can I find more information about this intervention, similar types of intervention, or related studies?