Effects of closed circuit television surveillance on crime
- Authors: Brandon Welsh, David Farrington
- Published date: 2008-12-02
- Coordinating group(s): Crime and Justice
- Type of document: Protocol, Review, Plain language summary
- Volume: 4
- Issue nr: 17
- Category Image:
- PLS Title: Closed Circuit Television (CCTV) as a crime prevention tool
- PLS Logo:
- PLS Description: This Campbell systematic review examines the effects of closed circuit television (CCTV) on property crime and violent crime. The review reports on whether using CCTV results in crime displacement, and also assesses whether using CCTV leads to the spread of crime prevention benefits. The authors found 44 evaluations. The studies were from the United Kingdom, the United States of America, Canada, Norway and Sweden. Most of the studies (34) were from the United Kingdom.
- Title: Effects of closed circuit television surveillance on crime
Closed circuit television (CCTV) surveillance cameras serve many functions and are used in both public and private settings. The prevention of personal and property crime is among the primary objectives in public space, which is the main focus of this review.
CCTV is viewed as a technique of “formal surveillance” and in this regard it is seen to enhance or take the place of security personnel. Results of this review indicate that CCTV has a modest but significant desirable effect on crime, is most effective in reducing crime in car parks, is most effective when targeted at vehicle crimes (largely a function of the successful car park schemes), and is more effective in reducing crime in the United Kingdom than in other countries. These results lend support for the continued use of CCTV to prevent crime in public space, but suggest that it be more narrowly targeted than its present use would indicate. Future CCTV schemes should employ high- quality evaluation designs with long follow-up periods.
In recent years, there has been a marked and sustained growth in the use of CCTV to prevent crime in public space in the U.K., United States, and other Western nations. In the U.K., CCTV is the single most heavily funded crime prevention measure operating outside of the criminal justice system. A key issue is how far funding for CCTV has been based on high quality scientific evidence demonstrating its efficacy in preventing crime. There is concern that this funding has been based partly on a handful of apparently successful schemes that were usually evaluated with less than rigorous designs, done with varying degrees of competence, and done with varying degrees of professional independence from government. Recent reviews that have examined the effectiveness of CCTV against crime have also noted the need for high quality, independent evaluation research.
The main objective of this review is to assess the available research evidence on the effects of CCTV surveillance cameras on crime in public space. In addition to assessing the overall impact of CCTV on crime, this review will also investigate in which settings, against which crimes, and under what conditions it is most effective.
Four search strategies were employed to identify studies meeting the criteria for inclusion in this review: (1) searches of electronic bibliographic databases; (2) searches of literature reviews on the effectiveness of CCTV in preventing crime; (3) searches of bibliographies of CCTV studies; and (4) contacts with leading researchers. Both published and unpublished reports were considered in the searches. Searches were international in scope and were not limited to the English language.
Studies that investigated the effects of CCTV on crime were included. For studies involving one or more other interventions, only those studies in which CCTV was the main intervention were included. Studies were included if they had, at a minimum, an evaluation design that involved before-and-after measures of crime in experimental and control areas. There needed to be at least one experimental area and one reasonably comparable control area.
Data collection & analysis
Narrative findings are reported for the 44 studies included in this review. A meta- analysis of 41 of these 44 studies was carried out; the requisite crime data was missing in other 3 studies. The “relative effect size” or RES (which can be interpreted as an incident rate ratio) was used to measure effect size. Results are reported for total crime and, where possible, property and violent crime categories using (mostly) official data. In the case of studies that measure the impact of CCTV programs on crime at multiple points in time, similar time periods before and after are compared (as far as possible). The review also reports on displacement of crime and diffusion of crime prevention benefits.
The studies included in this systematic review indicate that CCTV has a modest but significant desirable effect on crime, is most effective in reducing crime in car parks, is most effective when targeted at vehicle crimes (largely a function of the successful car park schemes), and is more effective in reducing crime in the U.K. than in other countries.
We conclude that CCTV surveillance should continue to be used to prevent crime in public space, but that it be more narrowly targeted than its present use would indicate. Future CCTV schemes should employ high-quality evaluation designs with long follow- up periods.