The lack of statistical significance may be more indicative of a small sample size than of the ineffectiveness of CCTV, which suggests the need for more rigorous evaluations in public transport settings. The crime reductions were not negatively impacted by displacement, with only 6 of the 50 studies incorporating an adjacent control area i. In three additional studies, researchers found some evidence of both displacement and diffusion of benefits.
Fifteen of the studies found evidence of diffusion of benefits, which suggests that CCTV may more often lead to unanticipated crime control benefits. Similar to the prior review, we also found the largest and most consistent effects of CCTV within car parks. The number of evaluations conducted in car parks increased slightly since the last review from six to eight.
Although it is difficult to disentangle the independent effects, several key factors played a role in car parks being the most effective setting for cameras to prevent crime. For one, seven of the eight car park studies included other interventions, such as security guards, signage, and improved lighting.
Also, a similar number of the car park studies were targeted on vehicle crimes and six were actively monitored. There is also the matter of camera coverage.
In the national U. Whereas the findings from the prior review revealed that car parks was the only setting where CCTV was associated with significant effects, the findings from our new review reveal evidence of significant crime reductions within other settings. Welsh and Farrington , a suggested that strategic aspects of CCTV schemes might be as important as the geographic setting. The findings of the current review provide further support for this observation. Schemes that incorporated multiple interventions alongside CCTV were associated with larger effect sizes than were schemes deploying single or no interventions alongside CCTV.
Actively monitored CCTV schemes evidenced significant reductions in crime, whereas passively monitored schemes were not associated with reductions in crime. Rather than relying on conspicuous camera presence, public safety agencies should employ active camera monitoring to identify and address proactively incidents of concern. Another intriguing finding relates to the absence of significant effects in the United States. Welsh and Farrington , a also found no significant effects in the United States. Given that the present review included 20 more evaluations conducted in the United States, however, the absence of significant effects in the United States is particularly noteworthy.
Given that the effect of CCTV is strongest in car parks, the general lack of car park schemes in the United States may help explain the lower effect in this country. Given that residential settings exhibited the second strongest effect, it is difficult to identify substantial patterns in the influence of settings across countries. Patterns of effect are much more evident in the manner by which public safety agencies use CCTV. In the United Kingdom, Furthermore, 12 Given the overall positive findings associated with active monitoring and the use of multiple interventions, these factors may help explain the difference in CCTV effects between the United Kingdom and the United States.
We also found that the effect of CCTV is heterogeneous across crime types. The largest OR effect size 1. Our findings indicate that despite such proclamations from drug sellers, CCTV cameras may help combat the illicit drug trade. These processes can be complex and difficult for police officers to observe on the street. They just served [sold drugs to] a guy in a white Lexus. CCTV was associated with significant reductions in both vehicle crime and property crime in general, with no significant effects observed for violent crime.
Public safety agencies combatting violent crime problems may need to consider whether resources would be better allocated toward other crime prevention measures. For jurisdictions with existing CCTV systems, public safety agencies may need to make changes to their existing strategies to combat violence effectively.
Actively monitored CCTV, which can detect incidents of concern in real time, may be able to deploy police officers on scene before a situation escalates into serious violence. This potential benefit of CCTV was observed by Piza, Caplan, and Kennedy in their systematic social observation of violent crime events recorded in their entirety i.
It should be noted, however, that actively monitored CCTV systems require a greater commitment of resources than do passive systems. There is no guarantee, however, that such technology will increase CCTV effectiveness. Upon detection of an image of concern such as a weapon, fugitive vehicle, or physical behavior indicative of crime e. This may bolster the efficiency of active CCTV monitoring as researchers have shown the bulk of camera operator time is spent on activities other than camera monitoring e. None of the evaluations we identified for potential inclusion in this review included a mention of the use of CVT.
Even with further policy insights from an increase in evaluations of CCTV, there continue to be opportunities for further improvement in evaluation research. For one, randomized controlled experiments are a rarity in the study of CCTV. Piza a : 16 noted that, because CCTV cameras are hardwired to physical structures and configured to wireless communications networks, moving locations after experimentation would require additional expenditures.
Nonetheless, random assignment of CCTV cameras may be possible in certain cases. As argued by Piza a : 27 , agencies could identify priority locations at the outset of a program and randomly select a subset of locations to receive cameras during the first phase of installation. Under this strategy, officials could simultaneously generate the most rigorous evidence of the effects of CCTV while ensuring that all priority locations received CCTV presuming that experimental results support the installation of more cameras.
In this sense, there may also be a role for redeployable CCTV cameras, meaning that experimental areas can be moved around. Future research should be aimed at continuing to ensure the policy relevance of CCTV research. In recognition of this fact, the College of Policing developed the What Works Toolkit to summarize the research evidence on a variety of crime prevention strategies in a format that is easily interpreted by practitioners. To generate sufficient knowledge on implementation issues and economic costs associated with CCTV, researchers may need to conduct systematic reviews aimed at prioritizing research that is directly focused on these factors, irrespective of whether crime was directly tested in the evaluation.
Last, researchers should expand the focus of CCTV evaluations to include more outcome measures than crime prevention. Although crime prevention is obviously an important consideration, police departments also invest in CCTV for its ability to detect and identify offenders for investigatory purposes Ratcliffe, Despite this potential benefit of the technology, a body of research on the investigatory benefits of CCTV has yet to develop. The field would benefit from an increased evidence base on the effect of CCTV on such outcomes.
His research is focused on the spatial analysis of crime patterns, crime control technology, and the integration of academic research and police practice. He received his Ph.
Brandon C. David P. Farrington , O.
Effectiveness and Evaluation of Crime Prevention Programs in Minas Gerais
His research interests include developmental criminology and crime prevention. He received the Stockholm Prize in Criminology. He has published more than journal articles and book chapters on criminological and psychological topics as well as books, monographs, or government reports.
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If the address matches an existing account you will receive an email with instructions to retrieve your username. Piza Corresponding Author E-mail address: epiza jjay. Farrington Cambridge University Search for more papers by this author. Tools Export citation Add to favorites Track citation. Share Give access Share full text access.
Share full text access. Please review our Terms and Conditions of Use and check box below to share full-text version of article. Policy Implications The results of this systematic review—based on 40 years of evaluation research—lend support for the continued use of CCTV to prevent crime as well as reveal a greater understanding of some of the key mechanisms of effective use. The OR is calculated from the following formula:.