Evidence-Based Policing Matrix
Micro Places – Ariel & Partridge (2017)
Ariel, B., & Partridge, H. (2017). Predictable policing: Measuring the crime control benefits of hotspots policing at bus stops. Journal of Quantitative Criminology, 33(4), 809-833.
Location in the Matrix; Methodological Rigor; Outcome:
Micro places; General; Proactive; Very rigorous; Mixed findings
What police practice or strategy was examined?
Mass transit stops such as bus stops and subway/train stations often represent crime hot spots within large cities. Consequently, the intervention examined in this study involved assigning uniformed officers to patrol a random sample of bus stops three times per shift for a period of 15 minutes each in London, England. While patrolling, the officers were only tasked to be “visible”, with the hope that their presence would deter crime. The intervention was operational Monday-Friday of each week from 12:00-20:00 to coincide with “peak times” for crime opportunities, and so officers were present when passengers were boarding/disembarking the bus.
How was the intervention evaluated?
In total, 102 bus stops were selected for inclusion in the study, half of which were randomly assigned to the treatment. Crime was measured using incidents flagged as “Community Safety” within the Driver Incident Report (DIR) system. These data were then compared for both groups to the corresponding data from the same period in the previous year, with additional analyses exploring outcomes based on operational versus non-operational hours, as well as the treatment area (approximately 50 meters (m) around the bus stop) versus catchment areas of 50m-100m and 100-150m around the bus stop. The researchers also evaluated the effectiveness of the intervention using crime outcome data corresponding to the number of victim-generated reports to the Metropolitan Police Service.
What were the key findings?
The intervention produced mixed findings. During operational hours, DIRs were reduced by 37% in the immediate treatment area (~50m) and by 40% in the 100-150m buffer areas surrounding the bus stop, compared to control areas. While there was evidence of displacement in the 100-150m buffer areas during non-operational hours, these displacement effects were not statistically significant across all hours and days. When considering victim-generated crime data, however, the authors report a significant backfire effect. During operational hours, victim-generated crimes were significantly higher under the treatment condition for all radii when compared to the control condition; there was an increase in victim-reported crime of 25% in the 50m region, 23% in the 50-100m region, and 11% in the 100-150m region. Victim-generated crimes were not analyzed outside of operational hours.
What were the implications for law enforcement?
The authors suggest that hotspot police patrols are only effective if conducted in a way that maintains unpredictability. Due to the way in which the intervention was designed, officers patrolled a small area over a period of 6 months and followed a very structured and routinized schedule which may have reduced unpredictability. Thus, the authors propose that because prospective offenders were potentially able to anticipate when the officers would leave (or return), the deterrent effects of the intervention were limited to those short windows when the officers were physically present at the bus stop. The increase in victim-reported crime in the treatment areas may be a reporting effect of the intervention.
Where can I find more information about this intervention, similar types of intervention, or related studies?
- All studies in the Matrix on micro places
- More Information on Hot Spots Policing (CEBCP Webpage)
- Sherman and Weisburd (1995) study on general deterrent effects of patrol in crime hot spots
- Koper (1995) study on optimizing patrol visits to crime hot spots
- Telep at al. (2014) - How Much Time Should Police Spend at Hot Spots? (Randomized Field Trial)
- Braga et al. (2019) systematic review of hot spots policing