Evidence-Based Policing Matrix
Micro Places – Bryson (2019)
Study Reference:
Location in the Matrix and Methodological Rigor:
Micro places; General; Proactive; Moderately Rigorous; Mixed effects
What police practice or strategy was examined?
This study examined the impact of increased police patrols within hot spots on crime and calls for service in Kansas City, Missouri. The research team identified 16 areas, each approximately 0.25 square miles, that had high rates of violent crimes and calls for service. Five of these areas were randomly assigned to receive additional police visits, and six served as a control group (another five areas were designated for a network-based intervention, which was not the primary focus of this study). With support from overtime fundings, officers were instructed to conduct additional proactive patrols in the treatment hot spots 2-4 times daily, depending on the day of the week. Each patrol was planned to last an average duration of 15 minutes, adhering to the Koper Curve (1995) principle of hot spot patrols. As implemented, one hot spot received the planned number of daily visits (almost 3 per day), and the others received an average of less than two visits per day. More than half of the visits (58%) were within the targeted 10-15 minute range and 31% were longer. The intervention took place over a 60-day period from August 1, 2017, through September 30, 2017.
How was the intervention evaluated?
To evaluate the effectiveness of the intervention, the researcher compared incident reports for several offenses (including violent crimes, theft, disorder, destruction, and drug offenses) and high-priority calls for service per week. This study focused on three types of calls: Priority 1 calls which involve immediate or extreme danger, Priority 2 calls which involve potential harm, and Priority 3 calls which are non-life-threatening but still require police intervention. The analysis covered a period of 104 weeks before the intervention and the 9-week intervention period. To account for seasonal fluctuations in crime rates, the researcher also compared the change in priority calls and crimes during the intervention period with those during the same 9-week periods in the preceding two years. Furthermore, the researcher tested for any potential displacement of crimes or diffusion of benefits to surrounding areas.
What were the key findings?
There were statistically significant decreases in high priority calls for service in both the treatment and control areas, but the changes were greater in the treatment areas, particularly for priority 1 calls. Findings for other offenses were mixed, largely non-significant, and did not provide clear evidence of effects from the patrols. Notably, violent crimes declined in the areas immediately surrounding the treatment locations, consistent with a diffusion of benefits pattern, but they increased within the treatment and control locations.
What were the implications for law enforcement?
In this study, the police conducted directed patrols during their overtime hours. However, the patrols were executed during only 68% of the planned shifts due to the reliance on overtime. The author suggests that the effectiveness of directed patrols in hot spots could be enhanced if they are conducted in brief intervals between calls during officers' regular shifts rather than relying on overtime, which in this case limited the frequency of the patrols. Despite mixed findings, the study indicates that an increased police presence in hot spots has a positive impact on calls for service, which could lead to a more efficient use of policing resources. More precise targeting of the patrols on smaller micro hot spots might also enhance effectiveness, as shown by several other studies of hot spots patrol.
Where can I find more information about this intervention, similar types of intervention, or related studies?