Wednesday, July 09, 2008

CCTV proponents should abandon claims that surveillance cameras reduce crime

John Honovich, a consultant on video surveillance and biometrics, says in a meta-analysis of recent studies of CCTV effectiveness that the industry needs to change its marketing pitch. Particularly it must stop promising the public CCTV can reduce crime, primarily because virtually all the research on public CCTV use shows that it fails to reduce crime. As a result, Honovich makes the following suggestion for CCTV proponents:
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.
Honovich says CCTVs more important use is in solving crimes, citing the much-different reasons usually articulated for private sector adoption of cameras. So far, he says:
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.
So Honovich thinks public surveillance proponents have merely framed the problem incorrectly, that the studies showing negligible effects on crime mean that proponents must change their pitch. But if we're to judge CCTV by its effectiveness, what are we to make of news from the UK that in London, the most surveilled city on the planet, surveillance footage is used to help solve only 3% of street robberies?

A British detective writing in 2006 declared "CCTV viewing occupies a dis-proportionate amount of police time with very little tangible result," and that "identification is rarely assisted by CCTV" in police investigations. Typically, he said, the "footage will show that some kind of offence has taken place. It is more than useless for the purposes of finding out who did it."

Video surveillance works better when focused on low-traffic areas and high-value targets, which is how the private sector uses it - to protect specific assets. For example, cameras would have been a useful security measure in recent thefts from southeast Texas police property rooms. Parking garages are another area with low-traffic but high-value targets where studies show cameras provide added protection.

But general public surveillance? Not so much. According to the UK Guardian:
Use of CCTV images for court evidence has so far been very poor, according to Detective Chief Inspector Mick Neville, the officer in charge of the Metropolitan police unit. "CCTV was originally seen as a preventative measure," Neville told the Security Document World Conference in London. "Billions of pounds has been spent on kit, but no thought has gone into how the police are going to use the images and how they will be used in court. It's been an utter fiasco: only 3% of crimes were solved by CCTV. There's no fear of CCTV. Why don't people fear it? [They think] the cameras are not working."
IMO Honovich overstates the case when he says that "Widespread consensus exists that CCTV is effective in reducing premeditative/property crime." I don't think there's evidence that CCTV in public places reduces property crime. Used for specific high-value targets or in areas with limited access (e.g., the car park or police evidence room examples), there's a consensus cameras provide a significant added layer of security, but that's a more limited claim.

Even with Honovich's focus on solving crime instead of reducing it, the cost-benefit analysis for public camera surveillance hardly supports its use by police. Citing how much cheaper cameras have become and reduced costs for transmission systems, Honovich suggests that proponents of CCTV adopt a new metric to promote their product: Cost per camera. He writes:
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.
This is a useful but IMO incomplete suggestion. A better metric would be "cost per crime solved using cameras." Simply measuring (or reducing) the cost per camera alone tells us very little about whether those cameras are making us more secure.

The studies Honovich cites have usefully demonstrated that, despite massive public investment in the UK in particular, surveillance cameras do not reduce crime on the front end. We also know that in a small number of criminal cases, they help solve them on the back end, though they're more likely to do so when cameras are focused on high-value targets and/or low traffic areas. Even so, cameras are easily defeated by low-tech means like hats, scarves and sunglasses, and at best provide only a small additional increment of safety when they're deployed.

The question now becomes: Is that increment worth the massive costs associated with installing and monitoring public CCTV surveillance? So far, most of the evidence says "no," but I welcome the introduction of new metrics to measure the question.

Hat tip to Bruce Schneier.

UPDATE: Noam Biale of the national ACLU emails to ask if I'd post a link to the organization's recent white paper on surveillance camera effectiveness, so here you go (pdf).


Anonymous said...

Hi Scott, Thanks for a very informative and well researched post.

A couple of posts to consider:

- You cite that only 3% of street robberies are solved in London. In that same Guardian article, it also states that a new scheme they are using solves 15-20% of robberies.

- You cite a British detective in 2006 that claims that cctv "is more than useless for the purposes of finding out who did it." This is why I recommend switching away from PTZs and moving to megapixel cameras. In the last few years, megapixel cameras have really matured and is widely commercially available. This will make a tremendous difference in providing highly quality evidence available that results in prosecution. So I agree with you on the historical point but I believe that new systems will significantly improved due to better commercial off the shelf technology.

- I agree with you completely that a metric of cost per crime solved should be targeted and tracked. I hope our discussion hopes to encourage community members to consider this.

Thank you,


Gritsforbreakfast said...

Thanks John,

IMO it's a stretch to attribute the 15-20% decline to cameras, since the Guardian story says that's only true for selected districts and attributes the decline to testing "a London-wide database of images of suspects that are cross-referenced by written descriptions." For anybody outside London, that database doesn't exist so those crime reduction rates couldn't be expected, even if London can sustain them beyond the pilot.

As for improved cameras, the problem with that is governments have spent billions worldwide on cameras they already installed. Even if improved cameras are cheaper, replacing them is costly and time consuming.

Which brings me to one more quibble with your piece I forgot to mention: your assertion that the main cost for CCTV was transmission. I agree that's true for the hardware, but the ongoing cost includes monitoring resources and investigator time spent (wasted?) combing through hours of video. So while cameras are cheaper than police, as you point out, if you're actually going to employ people to monitor them in an effort to prevent crime, that gets to be a lot more expensive.

Finally, I'm curious what you think about the distinction between reducing property crimes in public spaces vs. for specific targets? To me that seems like the crux your and my differing interpretation of the studies so far - I don't read them to say cameras reduced property crimes in public spaces, only in car parks and other places where they're focused on high-value assets.

Thanks for stopping by, and thanks especially for compiling that excellent list of CCTV references!

Anonymous said...

Exellent article.

In my estimation, despite failure of public surveillance to either reduce or solve incidents the emphasis on increasing installed cameras will accelerate.

The Brit home sec stated it very succinctly after the summer bus bombs; 'we're all suspects now'; and that's the future, we're all suspects to be churned through the automated id systems.


Anonymous said...

Isn't the use of cameras all about displacement of crime? Cameras aren't mobile like criminals. Besides, it seems to me, and I could be wrong, that cameras are put in hot spots. When the criminals move on, then the cameras become basically useless.

Anonymous said...

There's actually a couple of fairly obvious points which are conveniently overlooked when considering the effectiveness of video surveillance.

Firstly, the hugely expensive academic research counts for little, if you consider that it's sole purpose is to relate effectiveness against what has historically been done.

There is absolutely no comparative research (that I'm aware of ...) anywhere around the globe, which relates what has been done, against what could have been achieved if the CCTV systems were correctly profiled, designed, installed and operated in the first place.

The deployment of CCTV across the UK was driven not so much by operational objectives, but rather political enthusiasm, which means that no money was spent on researching and devising the most appropriate techniques for any given situation.

The idea that a PTZ or remote control dome camera can somehow provide the ultimate tool in terms of Forensic Surveillance, is patently a nonsense, and given that operational efficiency is generally around 2 - 5% overall, it's easy to see why huge sums of investment have resulted in systems which are often little more than a naive exercise in "lottery surveillance".

The belief that IP Video and Megapixel cameras will revolutionise surveillance, only holds true to the extent that the technology must be correctly deployed within the requirements of the Criminal Justice System, for which hopefully it is there to serve.

The Pro's and Cons of CCTV were well understood by a few, even 15 or 20 years ago. It's just unfortunate that those with little or no experience of the subject believed they knew more, and the results (or almost total lack of ...) are now plain for all to see (provided of course they are actually prepared to look!).

Whilst a cost benefit analysis based on crime reduction / detection could be produced, in practice, cities like London will always have a wider role for CCTV Systems (including of course Counter Terrorism / Homeland Security and Incident Management), neither of which lend themselves terribly well, to more detailed number crunching.

The bottom line is that although the U.K. is currently moving through a third age of surveillance, it's lessons are still not being learned, at a time when cities around the world are rushing to catch up, without paying due heed to the warnings and recommendations of those in the know.

Anonymous said...

This is a very well done post, with some thought provoking points. While I agree that it's virtually impossible to prove a negative, such as how much crime is prevented through the use of surveillance cameras, it is indeed well documented here in the U.S. as well that security cameras have contributed to a much higher solve rate than in the years prior to more widespread camera usage.
eos Barbara

Gritsforbreakfast said...

Barbara, that's just not true. Clearance rates wend DOWN in the US during that period. Fewer crimes were solved overall, not more.

Anonymous said...

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Anonymous said...

IP Video technology will greatly reduce the number of video displays required to monitor large scale systems, the number of personnel required to monitor the displays, and the server or recorder capacities needed to record all pertinent action in real-time at full frame rates. These are all contributing factors to further reducing the total cost of ownership for networked systems and incentives to deploy IP-based systems setups.
The Content analytics can be applied to both live and recorded video, with multiple detectors and unlimited detection rules per camera, as well as offering increased functionability with analytics on edge devices. Megapixels is simply the horizontal dimension multiplied by the vertical dimension in pixels. if your size image is 2048 X 1536 (resolution), thus a 3,145,728 pixel image rounded to 3.2 Megapixel. Mega means million. This is the high quality IP megapixel security camera for your most high importance needs. Quality is the amount of compression applied to the image in the camera. The higher the quality (less compression) the larger the file size will end up being.

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Outdoor Security Camera System said...

I have an idea to create a device that will alert someone of the presence of wireless video transmissions on the 2.4 gHz band. Im basically attempting to create a device that will detect surveillance cameras and then alert you of its presence. The alert is experienced in the sensation of a bracelet that will SQUEEZE your arm.

Harold | cctv said...

Did you know the UK has 30% of the entire planet's cctv cameras. We also have more cameras in Croydon than in New York.

4,000,000 cameras and now the government wants another 2,000,000

Who's going to be watching all these cameras? Dear oh dear.

Wireless Security Cameras said...

You raise an interesting point. However,surveillance cameras might not reduce but they definitely deter crime. A person will think twice about robbing a place with an extensive cctv network than a place with just a locked door. After all, the chances of getting caught with the help of CCTV systems are much higher than getting caught without one.

However, people who want to steal will steal no matter what. So in the heat of the moment they will not think about the CCTV network recording their moves but about the money or goods they can potentially steal from a place.

POS Systems said...

CCTV deployment across the UK was driven not so much by operational objectives, but rather political enthusiasm, which means that no money was spent on researching and devising the most appropriate techniques for any given situation....
keep sharing such stuff...

charlie said...

just two good reason why you should install CCTV

1. Deter Criminals

One of the primary benefits of a video security system is to deter a criminal act from ever happening. Well placed cameras will give would-be criminals reason for pause, or send them looking for locations less prepared.

2. Prevent Theft

The average cost of crime for a small business is around £13.354 per year and given the current economic conditions and ease at which criminals can move stolen products, risk of both internal and external theft has skyrocketed. It’s proven that a simple video security system can easily stop it. Make sure your organisation doesn’t become part of these statistics. You can protect it from only £1200 per year.