A Longitudinal Quasi-Experimental Study of Violence and Disorder Impacts of Urban CCTV Camera Clusters

• Author: Jerry H. Ratcliffe,Elizabeth R. Groff
• DOI: 10.1177/0734016818811917
• Published date: 01 June 2019
• Date: 01 June 2019
• Subject Matter: Articles

Article

A Longitudinal

Quasi-Experimental Study

of Violence and Disorder

Impacts of Urban CCTV

Camera Clusters

Jerry H. Ratcliffe

1

and Elizabeth R. Groff

1

Abstract

Methodological challenges have hampered a number of previous studies into the crime reduction

effectiveness of closed-circuit television (CCTV) surveillance systems. These have included the use

of arbitrary fixed distances to represent estimated camera deterrence areas and a lack of control for

camera sites with overlapping surveillance areas. The current article overcomes the first of these

challenges by using camera view areas individually constructed by researchers viewing and manip-

ulating cameras to determine precise camera viewsheds. The second challenge is addressed by

grouping cameras into clusters of combined viewshed areas. The longitudinal crime and disorder

reduction effectiveness of these clusters of overlapping CCTV cameras is tested in Philadelphia, PA.

Multilevel mixed-effects models with time-varying covariates and measures from a noncomparable

control area are applied to 10 years of crime data (2003–2012) within the viewsheds of 86 CCTV

cameras grouped into 13 clusters. Models applied across violent street felonies and disorder inci-

dents find no significant impact associated with the introduction of CCTV surveillance. Potential

reasons for this are discussed.

Keywords

ecology and crime/spatial analysis, crime/delinquency theory, crime prevention, law enforcement/

security, property crime, other

The use of closed-circuit television (CCTV) video surveillance systems for crime prevention in

public places has grown rapidly in recent years (Lim & Wilcox, 2017). In the United States,

Washington, DC, New York, Baltimore, and Chicago have collectively spent more than

US$40 million (Klein, 2008; LaVigne, Lowry, Markman, & Dwyer, 2011). By mid-2012,

Philadelphia, PA (the site of the current study) had already spent more than US$17 million (City

1

Temple University, Philadelphia, PA, USA

Corresponding Author:

Jerry H. Ratcliffe, Department of Criminal Justice, Temple University, 1115 Polett Walk, Philadelphia, PA 19122, USA.

Email: jhr@temple.edu

Criminal Justice Review

2019, Vol. 44(2) 148-164

ª2018 Georgia State University

Article reuse guidelines:

sagepub.com/journals-permissions

DOI: 10.1177/0734016818811917

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of Philadelphia, 2012). CCTV systems have the potential to aid crime investigations, identify

offenders, streamline police response, increase punishment certainty, and reduce the public fear

of crime (Ashby, 2017; LaVigne et al., 2011; Piza, Caplan, & Kennedy, 2014; Ratcliffe, 2006).

When police have been proactively tasked based on activity observed by CCTV cameras, significant

reductions in violence and social disorder have been observed (Piza, Caplan, Kennedy, & Gilchrist,

2015).

Studies of urban public CCTV systems are increasing, though at the time of Welsh and Farring-

ton’s (2007) systematic review, they identified only 22 from 44 studies that were applicable to city

centers and urban public areas, and their conclusions were dominated by the results from public car

parks. The earliest independent evaluation of a CCTV implementation dates from King’s Lynn, UK

(Brown, 1995), where 19 cameras were installed at public car parks across the city; however like

many studies that followed, this evaluation suffered methodological issues such as a lack of controls

for low numbers of initial crimes and for long-term temporal trends. Overall, the existing CCTV

evaluation literature displays considerable variation in n ot only methodology but also outcome

measures and independent variables. Some studies examined the impact of cameras on crime within

a defined distance of CCTV cameras (Harada et al., 2004), while others surveyed residents in camera

areas for their perceptions of how crime has changed (Squires, 2003). Other studies have interviewed

key stakeholders (Hood, 2003) or examined emergency room attendance levels related to assaults

after the introduction of a CCTV surveillance system (Sivarajasingam, Shepherd, & Matthews,

2003). To date, few researchers have addressed the challe nge represented by camera viewshed

overlap that has theoretical and—more importantly—analytical implications (Lim & Wilcox,

2017, is a recent exception). Cameras in close proximity to each other with overlapping viewsheds

may not necessarily work independent of each other; instead their effect may be enhanced by the

presence of multiple cameras magnifying the deterrence signal to potential offenders.

This article reports the results of a quasi-experimental, longitudinal study of the violence and

disorder impact of 13 clusters of CCTV cameras (86 cameras in total) in the city of Philadelphia, PA.

After a brief overview of the theoretical rationales for CCTV implementation, the article describes

the methods, camera design, study setting, and the analytic approach. We report the results for two

crime types and summarize the findings before discussing them and offering implications.

Theory

CCTV cameras may reduce crime in a number of ways. Drawing on a rational choice and situational

crime prevention framework (Clarke & Felson, 1993; Cornish & Clarke, 1986), the prevention

mechanism most commonly argued is deterrence through a potential offender becoming aware of

a camera and deciding that the risk of their identity being captured outweighs the benefits of the

imminent offense (LaVigne et al., 2011; Piza et al., 2015; Ratcliffe, 2006). Within a situational

framework, CCTV camera schemes fall under the general approach of increasing the risks of

committing crime and represent a “formal surveillance” technique that enhances or replaces the

role of security staff or the police (Clarke & Eck, 2005; Welsh & Farrington, 2008).

In one study, police actively monitored the CCTV with the explicit intention of anticipating

trouble in a popular bar area of the town of Malm}

o, Sweden. When the camera monitor observed an

incipient disturbance, officers were dispatched to the scene to de-escalate situ ations or prevent

ongoing fights escalating (Gerell, 2016). Within the situational crime prevention framework, this

combination of technology and organizational response would seek to reduce provocations. How-

ever, most researchers hypothesize the primary mechanism is offender awareness of camera location

and that awareness will generate a change in the perception of risk and subsequently a reduction in

offending (Piza et al., 2015).

Ratcliffe and Groff 149