Is public CCTV effective?

July 12, 2008
Key findings and practical recommendations

[Editor's note: John Honovich publishes this and other information on network video at]

While we continue to spend more on public CCTV systems, the debate on CCTV effectiveness has reached a polarizing and inconclusive standoff. On the one side, you have a number of studies and leading thinkers who cleary contend that CCTV systems are ineffective. On the other, you have numerous municipalities who are weekly green-lighting new CCTV projects.

This report offers key findings from the 20 top studies/articles in the field and offers practical recommendations on how to optimize the use of public CCTV systems.

A directory of the 20 top papers in the field are included at the end of this document. This report is based on those papers.

Key Findings Summary

  • The expectation that CCTV systems should be deployed to reduce crime rather than solve crime has created huge problems.

  • While the studies show serious doubt on CCTV's ability to reduce crime generally, a strong consensus exists in CCTV's ability to reduce premeditative/property crime

  • CCTV is consistently treated as a singular, stable technology, obscuring radical technological changes that have occurred in the last 10 years

  • Differences in per camera costs are largely ignored, preventing policy makers from finding ways to reduce costs

  • Routine comparison of police vs cameras is counterproductive

Practical Recommendations Summary

  • Stop claiming that CCTV can generally reduce crime

  • Optimize future public CCTV projects around crime solving rather than crime reduction

  • Optimize future public CCTV projects around material and premeditative crimes

  • Target technologies that support crime solving and material/premeditative crimes

  • Focus on minimizing cost per camera

Finding: Crime Reduction vs Crime Solving

The overwhelming majority of studies focus on analyzing CCTV's ability to reduce crime. The general approach is to take current crime statistics for a region and compare those statistics to the period after installation of CCTV. A number of techniques are used to adjust to control for general changes in crime and to track displacement or diffusion of benefits to other areas. Nevertheless, the focus of all quantitative analysis has been on reducing crime.

This is the mirror opposite of the private sector. In the private sector, the overwhelming majority of CCTV systems are justified by their use in solving crime. It is investigations where most private businesses find value and return in their CCTV systems. For businesses, only a very small percentage of CCTV cameras are ever even watched. The systems pay for themselves by periodically being able to identify or prove a criminal activity.

This indicates a failure of expectations for public CCTV systems. In the private sector, when CCTV effectiveness is discussion, the assumption is usually that CCTV is used for investigations. By contrast, the focus on public CCTV effectiveness being determined on reducing crime sets a dangerous expectation that is difficult to achieve and likely to create dissatisfaction within the community.

The problem seems to be the fault of the original advocates of these systems, rather than a deficiency of the testers. The academics and researchers performing these tests were reacting to the expectations that the proponents of these systems made originally.

In the recommendations section, I will examine how we can move beyond this unproductive and problematic situation.

Finding: Reducing Crime Generally vs Premeditative/Property Crime

The media's main focus has been on whether or not CCTV reduces crime as a whole. This often has turned the issue into an all or nothing debate. The testing has also focused on the general impact on crime reduction but notable attention has been paid to different types of crime.

Widespread consensus exists that CCTV is effective in reducing premeditative/property crime. All the studies acknowledge this, even the ACLU's which otherwise is extremely negative towards CCTV. The most frequently cited example is the ability to reduce thefts in parking lots.

By contrast, the same studies widely agreed that CCTV demonstrated little or no affect on reducing crimes of passion. Incidents like public drunkenness or acts of rage generally did not seem to be affected by the presence of CCTV cameras.

This fits a broadly accepted rational actor model and the effect that CCTV cameras has on rational actors. Since CCTV cameras increases the risk that a criminal will be prosecuted for a crime, the criminal will respond accordingly. The cameras will affect the perceived risk/reward calculation. Common sense indicates that this impact is much more likely for property/premediated crimes than it would be for crimes of passionate, where by definition, people are not calculating the consequences.

Rather than engage in political debates over the issue in general, we should use this more nuanced knowledge to optimize our use of CCTV.

Finding: CCTV as Singular, Stable Technology

The studies overwhelming treated CCTV as a singular, stable technology. Only the UK Home Office Report of 2005 even acknowledged the issue of technological change. The rest of the studies do not even discuss differences in technology available. I do not fault them as the evidence available is limited to even conduct such a test. Nevertheless, differences in technology can make an extreme difference.

The studies cover a very broad time period. The oldest study I found was from 1994 with most of the studies available being performed in the period from 2000 – 2004.

The problem is that CCTV technology has experienced a dramatic transformation in that time period. This is somewhat similar to the type of change experienced with mobile phones going from big, bulky, limited and expensive to slim, powerful and ubiqutious. It is quite unfair to assess the question is CCTV effective, in any form, without factoring in the differences in the type of technology used.

The examples found in the studies were fairly shocking compared to today's mainstream CCTV systems. The clear majority of systems employed in the studies used VCRs. Even when systems used DVRs, most were recording under 2 frames per second. All of the systems used standard definition cameras. While none of the reports discussed the type of transmission systems, given that almost all the tests were from 2004 or earlier, it is extremely likely none of them were using IP networks for transmission. Though limited, the best discussion on this topic in the literature is the 2005 UK Home Office Report.

While none of this is the researcher's fault, not factoring changes in technology obscures crucial differences. In the recommendations section, I explore what types of technologies and how they can impact system effectiveness.

Finding: Differences in Per Camera Costs Largely Ignored

While most studies cited general cost numbers, the cost per camera was largely ignored. The most frequently cited number is the amount the UK home office has spent on CCTV (500 million pounds). However, only the 2005 UK Home Office study actually broke down the cost per camera. Since the studies were focused on determining if the crime rate was reduced, this element is understandable. Nevertheless, communities could save significant money and improve effectiveness by more carefully tracking the cost per camera.

Understanding the cost per camera is important to recognize changes in technology and to identify waste. The 2005 UK Home Office report indicated that cost per camera ranged from $7,000 pounds to $33,000 pounds for cameras installed in the late 1990s and early 2000s. The study does not clearly explain the cause of the cost differences.

In my experience deploying similar systems, the main driver of costs from this era is the transmission systems. Because these cameras are generally outdoors and distributed throughout a city, transmission systems need to be built to send the video from the camera to the monitoring center. The solution of choice in this time frame was proprietary analog fiber transmission systems. Such systems required expensive transmission equipment and almost always laying of new fiber. This routinely generated costs of thousands to tens of thousands.

By contrast, today, the solution of choice for transmission is IP networks. IP networks dramatically reduce the cost of transmission. IP networks replace proprietary analog fiber systems with low cost commodity IP equipment. IP Networks often can share existing fiber networks or connect to a telecommunication carriers system to greatly reduce or eliminate the need for new fiber or construction.

Finding: Cops vs Cameras Comparison Counterproductive

A frequent sentiment expressed by interviewees in both articles and studies is the preference for police officers versus cameras. While this is obviously understandable and I expect most every reasonable person would agree that police officers are preferable to cameras, this omits a crucial element.

Since police officers are so much more expensive than cameras, a comparison between the two is very misleading. According to the 2005 UK Report, the annualized cost per camera ranged from 600 to 3000 pounds. This is 1/15th to 1/80th the cost for a yearly police officer (including benefits, training, equipment, etc). In actuality, then the comparison is more like dozens of cameras versus an officer. Furthermore, given the significant price reduction in CCTV systems since most of the tests occurred, the comparison is now between hundreds of cameras and a single police officer.

Examined at a macro level, a similar distortion is apparent. Many of the articles and studies cite the 500 million pound UK Home Office spending over the last decade. Nevertheless, 500 million pounds for CCTV represents less than 1% of the spending on police officers during that time period.

Even if all funding on CCTV was transferred to hire new police officers, it would only increase funding by a very small percent. And, of course, a small percent increase in police officers would not be expected to dramatically decrease crime either.

This is an area where CCTV proponents have created unrealistic expectations that actually undermine their own cause.

Now, let's examine some recommendations:

Recommendation: Abandon emphasis on general crime reduction

Proponents of public CCTV systems should abandon the emphasis and claim that CCTV systems can reduce crime generally. Even if proponents ignore the fact that studies demonstrate this, clinging to this claim only creates greater debate and dissension.

By abandoning this claim, it will heal some of the major discord and allow all parties to focus on better uses of CCTV. Given the vastly improved quality of today's CCTV systems at greatly reduced prices, this should be reasonable to accomplish.

Recommendation: Focus Projects on Crime Solving

Just like the private sector has broadly adopted CCTV by focusing on solving crimes, the public sector should too. This would save communities money as certain features or cameras could be eliminated and designs could be focused on areas and technologies that help solve crimes.

This would simultaneously ease the impact on privacy as less attention and resources would be placed on trying to monitor systems live and thereby the risk of monitoring the innocent public.

Recommendation: Focus Projects on Material/Premeditative Crimes

To the extent that CCTV is used to support crime reduction, such efforts should focus on material/premeditative crimes.

Limiting the locations covered and monitored live to those areas with high rates of these types of crimes will maximize the probability those systems will be effective.

Recommendation: Target Technologies that Support Crime Solving

Though historically the camera of choice has been a PTZ, systems should emphasis the use of megapixel fixed cameras.

A PTZ, or Pan/Tilt/Zoom camera, can be controlled by an operator to look in many different directions and areas. PTZ cameras are favored by security operators as it allows them to control the camera in live monitoring. Two significant downsides exist for PTZs: One, they require a dedicated operator to use the cameras, incurring significant operation cost. Two, PTZs are generally bad for producing evidence because they miss everything expect for the area where the camera is momentarily positioned.

Megapixel cameras are far better fit for public places and crime solving. The cameras being used in the study are standard definition units with very limited abilities to view details. Much like the transition from film cameras to today's digital super high resolution cameras, CCTV systems now routinely employ megapixel cameras that provide dramatically greater detail. Such detail is key for public places that usually cover large outdoor areas. In this scenario, megapixel cameras give you the benefits of PTZ cameras because the detail allows zooming with the benefits of a fixed cameras' ability to always capture video of a set area. This is critical to crime solving because the camera needs to have an image if we are to use the evidence to identify or prosecute a crime.

Recommendation: Minimize Cost Per Camera

Given what we have learned from first generation systems and the advances in technology available today, we should be vigilant about tracking and minimizing the cost per camera. We now have a good sense of what works and does not work. We should optimize around that and ensure that we can keep costs per camera low.

The two key elements in minimizing costs is (1) ensuring that IP networks are leveraged and that (2) unnecessary funding is not spent for needless bells and whistles. By doing this, municipalities should easily be able to deploy systems for between 2,000 and 4,000 pounds per camera. This would drop the cost by 60% or more relative to historical standards.


With our extensive experience and knowledge, we must re-position goals, modify designs and economize our efforts:

  • Set the goals appropriately on tasks that can succeed: Crime Solving and Property Crime Reduction

  • Select technologies such as IP and megapixel cameras that improve performance

  • Ensure spending per camera is controlled and benefits from new technologies

With these practices, we can ensure both effective CCTV systems and a positive economic contribution to society.

Directory of CCTV Effectiveness Studies

The debate on the effectiveness of CCTV is amazingly complex. Dozens of studies done over more than a decade with frequently conflicting positions makes the situation hard to assess. This problem is magnified by the difficulty of finding reference material.

This directory provides a catalog of as many publicly available studies and reports I can find on the web.

About the author: John Honovich, PSP, is an independent researcher and consultant focused on the world of networked video surveillance. He is author of and has previously worked in product development and management positions at security technology companies such as 3VR and Sensormatic.