Evidence-Based Policing Matrix
Micro Places – Lai et al. (2019)
Study Reference:
Location in the Matrix and Methodological Rigor:
Micro places; General; Proactive; Rigorous; Mixed findings
What police practice or strategy was examined?
This study examined the effects of police-monitored closed-circuit television (CCTV) surveillance cameras on property crime and robbery in Taipei City, Taiwan. Between July 2009 and December 2011, nearly 12,000 CCTV cameras were installed on neighborhood light poles at sidewalks, roads, lanes, and intersections within plain view of pedestrians, bicyclists, motorcyclists, and drivers. The monitors were installed where the public expressed the greatest concern for their safety, such as shopping settings, night markets, parking lots, and metro exits. (The authors were unclear as to what extent police monitored these cameras.).
How was the intervention evaluated?
The authors employed a quasi-experiment to evaluate the effects of CCTV cameras on property crime and robbery. Twenty locations with more than 40 CCTV monitors were selected as the target sites. Each location consisted of at least two cameras pointed in opposite directions to expand the scope of the viewshed area, and no other non-police-monitored cameras were present within a 100-meter (328 feet) radius of each location. Another 20 non-CCTV sites were then matched to these target sites based on sociodemographic variables, crime problems, police activities, and land use. Each control site was near its target site but at least 200 meters away. Time series analyses were used to compare the incidents of four types of crime (theft from persons, vehicle theft, burglary, and robbery) occurring within the 20 pairs of target and control sites during a 27-month pre-installation period to the crime incidents during a 27-month post-installation period.
What were the key findings?
This study provides mixed support for the effectiveness of CCTV on crime reduction. Overall, all crime types in both treatment and control sites declined over time. The CCTV intervention did not significantly affect thefts from persons, vehicle theft, or burglary. However, the CCTV cameras were associated with a significant reduction in robbery during the post-intervention period in treatment sites.
What were the implications for law enforcement?
The authors suggest that although police-monitored surveillance cameras were implemented widely, their effectiveness seems limited. This study shows that the deterrent effect of CCTV on robbery appears to be greater than its effects on property crime. The authors also suggest two realities that may have muted the effects of the treatment: crime was already declining in Taipei before the CCTV cameras were installed, and Taipei already had a high density of CCTV cameras before the intervention. The authors hypothesize that CCTV cameras might have more positive effects in improving criminal investigation results rather than deterring crime. They also suggest that more proactive strategies are needed to prevent crime rather than just CCTV installation.
Where can I find more information about this intervention, similar types of intervention, or related studies?