Why Surveillance Cameras Don't Reduce Crime

As a resident of the UK in South London, I am only to aware that the cameras do not work.

The main problem is one of cost, security in any form costs a lot of money it's supposedly costs UK businesses and home owners 4 Billion GBP (8,000,000,000 USD) This is not including the Government spend on the Police etc.

One effect that has been noticed is that initially crime moves away from the cameras which is why they are often touted as a success. However within a short period of time the crime returns. Usually the criminals have baseball caps and hooded tops etc to hide their identity, and "do the job" very quickly.

The criminals obviously know that a camera like a burgler alarm only represents a threat when you don't know how to alow for it in terms of time, identification hiding etc.

The simple fact is that you need a human elerment on the ground (Police etc) that can respond quickly.

Oh the big plus point for security cameras in the UK is that you can use them for making money, you just sell the video footage of the criminals etc to who ever wants to buy them.

The latest Idea is to cover the UK with special cammeras to pick up unlicenced car drivers, so the secret is out they are now just there to make money, like the Gatsos and other "traffic calming" technologies.

Sorry if I sound a bit cynical about CCTV and other cammeras, but I cannot walk out of my front door without being observed by atleast two cammeras, and still be in view if I walk the three or four miles into my local town center. Oh and the violent crime etc on my road and the surrounding area has gone up for the last three years.

Posted by: Clive Robinson at March 31, 2005 11:49 AM

Security cameras have the effect of making people (falsely) _feel_ safer and as a result they reduce the use other security measures (such as not locking the back door or not using the house-alarm) and thus making the robbers' job much much easier. This is a classic example of an unintended consequence.

Posted by: Saar Drimer at March 31, 2005 01:06 PM

Bruce, do you agree or disagree? The link you provided might actually be interpreted to say the opposite of your title. For example, the writer suggests:

"I don't know anybody, though, who thinks there shouldn't be a camera behind the counter at the convenience store."

Hmmm. If they (you) think surveillance cameras do not reduce crime, then why would they say all convenience store counters need one?

Or are you actually trying to announce something similar to "guns don't kill people..."; something catchy like "cameras don't stop crimals, cops do, so we need more cops"?

Posted by: Davi Ottenheimer at March 31, 2005 01:48 PM

Maybe the problem is that we don't have ENOUGH surveillance. David Brin writes about what he calls a "transparent society" in which surveillance cameras are everywhere. Then, criminals could be tracked from the scene of the crime back to their lair. Wearing a hat or a hood would not help them because they could be physically traced and arrested.

Posted by: Cypherpunk at March 31, 2005 02:15 PM

Roughly twenty years ago, radar/traffic cameras were tested in (I believe) Friendswood, TX to catch speeders (it's a crime, too). The test failed as the cameras couldn't differentiate between the judges, police and other members of the mandarin court and the little people. I wonder if and when surveillance will become so pervasive as to be opposed by the privileged.

Posted by: John Navratil at March 31, 2005 02:25 PM

Imagine my surprise at yet another article posted here in which yet another attempt at security is denounced.

Bruce is always quick to point out what *isn't* secure, but we've still heard nothing from him about what security practices he *would* recommend.

Apparently, we're all screwed. There's nothing we can do, so let's all simply not do anything!

Oh, wait, that's not secure either.

Posted by: Eric K. at March 31, 2005 02:30 PM

Bruce, you know, the more I think about this, the more I wonder what you might be thinking by annoucing to the world that surveillance does not reduce crime.

Yesterday your log mentioned the futility of trying to avoid identity theft. Fine, as Eric K. points out you seem to say we're all screwed. Maybe you are depressed about the state of things.

But let me point out that C. Drake made a brilliant comment about a real-life case where a guy tracks down and successfully gets his ID thieves convicted. You should check it out. In particular, you should make note of the part where the victim states:

"In Portland, the police department is so strapped that unless it's a person-to-person crime, it's pretty low priority."

Why does he mention this? It's because the victim is hot on the trail of the thieves and is standing at the same register where his identity was stolen, and he wants the police to respond. Instead, he's working the case himself. Note:

"I hop in the car and drive down to Denny's and ask to speak to the manager. [...] I pulled out my Visa. 'This card was used here this morning. Someone has seen the thief. I know your registers store the day's credit card transactions. Is there any way you can look up this number and tell me who served them?'"

Yeah, that's right, a CAMERA would help catch the bad guy. Ever step up to a bank teller and wonder why there is a dedicated camera pointing right at your mug? Perhaps it is because it performs a preventative as well as detective control function for security.

Granted, the ACLU researcher you linked to has some interesting questions that need to be answered, and maybe you were in a rush to post a title, but today's log needs serious clarification.

Posted by: Davi Ottenheimer at March 31, 2005 03:10 PM

Surveillance cameras are about as good as locks... they are made to keep the honest individual honest in a timely fashion... and really nothing more than evidence that a crime has occurred at one point in time.

Israel Torres

Posted by: Israel Torres at March 31, 2005 03:38 PM

Mr. Ottenheimer,

I'm the author of the linked post, and though obviously I wasn't clear, I'm not arguing against camera placement in convenience stores because those are private cameras and the store owner can do what they want. I'm arguing against cameras used by the government, by law enforcement, particulary in public areas.

Anybody can toss out hypotheticals, but the longitudinal study from Britain cited in the Grits post found that generalized camera surveillance empirically did not reduce crime, although in narrowly defined circumstances (especially parking facilities) they measured some benefit. Historically, when the government installed cameras, the motivation was essentially a hunch that they would help, but it was an intuitive leap, not a proven fact. Now, studies like the one by the British Home Office are identifying precisely where cameras prevent crime and where they don't. Using them elsewhere, I'd argue, is a waste of police resources as well as unnecessarily invasive of privacy. Best,

Posted by: Scott at March 31, 2005 05:17 PM

By the way, Bruce, thanks for the link! I just bought a copy of Secrets and Lies I'm planning to read over the weekend, so it's a timely honor.

Posted by: Scott at March 31, 2005 05:21 PM

Perhaps some of those commenters who have merely skimmed the article may have missed the link to the official United Kingdom Home Office criminological research study headed by Professor Martin Gill:

"The impact of CCTV: fourteen case studies"

This confirms previous studies, that CCTV in the United Kingdom (we have far more experience of it than most other places in the world) does not decrease crime or the fear of crime, for various reasons, which include the fact that many CCTV schemes are not linked to expensive control rooms which are properly manned 24 hours a day, 7 days a week.

CCTV does not have much of a deterrent value if the criminals do not actually know that they are under observation. What is the point of a warning sign which you cannot read in the dark, although the CCTV surveillance camera may have night vision, or which is beyond your visual range, even though the camera has powerful optical and digital zoom capability ?

Most CCTV systems have far more cameras than warning signs (some have no visible warning signs at all), which is the wrong way around, if they are meant to act as a deterrent.

Apart from the poor quality of many CCTV images from older systems, especially ones which use analogue video recorders and which often re-use the video tapes too often, and never pay to have the camera lenses cleaned periodically, there is the whole problem of actually positively identifying someone even from a good quality image.

Human beings are even worse at positively identifying faces from CCTV, than they are in picking out suspects from a police line up. The failure rate is somewhere between 40 and 50 percent.

Then there is the whole question of actually using CCTV footage as hard
evidence in court. Most systems simply have not invested in the duplicate signed copies, sealed evidence bags, independent evidence custodians etc. that are needed to provide a court of law with an unbroken chain of evidence, showing that it has not been tampered with.

A date time stamp on a printout from a CCTV monitor can be faked on the most basic of personal computers, and far more sophisticated video editing and manipulation tools are easily available, especially for digital systems where there is often no physical evidence of tampering, which can sometimes be detected with analogue tapes.

Consequently CCTV footage is rarely, if ever, presented directly in court, where it might be challenged frame by frame. Not every trial is a Rodney King or OJ Simpson media event.

The same is true for all the "add on" technologies which go well beyond simple video CCTV, which are being tested and deployed e.g. Automatic Number Plate Recognition, facial recogniton, "gait" (how you walk) analysis, "Suspicious behavior" anlaysis (how long you linger near a "protected" object), whether you appear to be engaged in "stabbing" or "kicking" motions etc. all conducted in the visible light or infrared spectrums, with or without photon multiplier image intensification.

Then there are the controversial and voyeuristic "see under your clothes" or "see your child naked" imaging technologies like Passive Millimetre Wave, Teraherz, Ultra Wideband and Low Intensity Backscatter X-Rays imaging etc.

These technologies cannot be dis-invented, and they have their place in the armoury of anti-crime and security tools, but they are simply not a technological magic fix for societal problems, especially where they are somehow promised as being "cheaper" then employing police or security guards "on the streets".

Posted by: Watching Them, Watching Us at March 31, 2005 05:28 PM

The essay quoted is quite correct insofar as it goes. I also note a story that is of some peripheral interest: http://news.bbc.co.uk/2/hi/uk_news/4392631.stm

However, while monitoring cameras so as to detect crime might not be productive, using the tapes as an aid to solving a crime appears to work quite well.

Posted by: Peter at March 31, 2005 05:32 PM


"Aussie man reports crime in Devon

The Octagon kiosk is covered by webcam
A man in Australia tipped off police in Devon after seeing a suspected burglary on a webcam based in Exmouth."

"It transpired the pair were a man and a woman having an argument, not conducting a burglary"

A false alarm, even one reported from the other side of the world, is still a false alarm.

Posted by: Watching Them, Watching Us at March 31, 2005 06:04 PM


Thanks for clarifying. I understand your position: "I'm arguing against cameras used by the government, by law enforcement, particulary in public areas. Anybody can toss out hypotheticals, but the longitudinal study from Britain cited in the Grits post found that generalized camera surveillance empirically did not reduce crime."

If you take Bruce's log entry "Why Surveillance Cameras Don't Reduce Crime" and read your post, and then read the study, you have to wonder why the log entry wasn't titled "How to Reduce Crime with Surveillance Cameras" or "How to Effectively Deploy and Manage Surveillance Cameras". Alas, Bruce simply stated that Cameras do not reduce crime....

What you have happened upon is an opporuntity to make Surveillance technology more effective in reducing crime. All I ask is that while in hot pursuit of Civil Liberties you try to avoid throwing out the baby with the bath water.

Surveillance technology is just now reaching a period of innovation and adoption that will make it a relevant and useful tool in prevention as well as detection of crime. We would be remiss to blame the failure of the deployment and administration of cameras on the devices themselves, on Bobby's or even British culture:

Posted by: Davi Ottenheimer at March 31, 2005 07:02 PM

I'm not sure that I'd say that security cameras, even the sort of science-fiction see-all network scenario proposed earlier, are going to deter crime, simply because they don't target the reasons why people commit crimes in the first place. Nor would I think it feasible to use tapes or files from such devices in court, because proving something "beyond reasonable doubt" is such a big ask when you have to convince a jury. Muddy the waters enough with timestamps and grainy images, and any jury will get confused.

But I see them as just another tool in detective work. Use them in conjunction with other techniques to find suspects or reduce the pool to a number that can be dealt with by other means. A good cop can usually work out in an interview if a suspect is worth investigating further to gain hard evidence that can be used in court, such as through a search, or through evidence from third parties, or records from banks and other institutions with reasonable security on their information.

What concerns me about these things is whether they are cost-effective. If they aren't delivering results, then it makes no sense in spending the community's money on employing people to bore themselves rigid watching a dozen monitors at once, or worse, to amuse themselves by prying into the lives of community members, such as zooming a camera down the top of a pretty girl, or following the progress of a romance in a side street. Add in infra-red or x-ray capability and you are just asking for misuse.

To my mind, the answer in using surveillance cameras as a crime-fighting tool is to make police departments pay for them out of their normal budgets. If they get results, then they will be paid for. If not, then the money and manpower will be diverted to more productive endeavours.

Posted by: Peter at March 31, 2005 07:12 PM

We can complain about the CCTV technology, or we can gather up a list of requirements and map it to the emerging technology. The fact is, the failures of existing and past surveillance technology is being addressed and improved fairly rapidly, if not exponentially.

Quite frankly, I find more people ask for surveillance than not these days when we talk about how to feel safe when walking to their car, standing in elevators, etc. (as the study rightly identifies). This should take us directly towards the reason why I am happy to see that the ACLU is interested in the issue: when people realize security is FOR them and not to be used AGAINST them, they generally can't wait to sign up. The problem is therefore mainly about restoring trust in public spaces, so I look forward to hearing the ACLU's recommendations on how that can be accomplished today. Sorry, no hypotheticals allowed.

Posted by: Davi Ottenheimer at March 31, 2005 07:16 PM


you said,
The latest Idea is to cover the UK with special cammeras to pick up unlicenced car drivers, so the secret is out they are now just there to make money, like the Gatsos and other "traffic calming" technologies.

I think you'll find the issue with unlicensed drivers, is that that also means their insurance may not (will not?) pay out in the case of an accident.

Before you see this as 'revenue' raising, consider the issue of someone you know/love being hit by a car driven by an unlicensed driver. Any expensive medical bills, future treatment and payouts you may expect to receive for care may not be forthcoming.

Finally, as to speed cameras, if you don't want to pay, don't speed. It's actually that simple.

Posted by: Anonymous at March 31, 2005 08:39 PM

"Apparently, we're all screwed. There's nothing we can do, so let's all simply not do anything!"

The Register has an interesting perspective on the problem you identify:


"But why, asks a reader, has the MSM [mainstream media] ignored [Spam King Richter's bankruptcy]? Probably because after a decade of libertarian propaganda, a kind of weary fatalism has set in."

Email is an excellent example of a the challenge of technical evolution and mainstream adoption with regard to a "throw up your hands and quit" approach. Spreading gloom and doom does not negate the fact that regulation is a big piece of the puzzle (along with technical and security innovations).

So Bruce, let's see some innovative and pro-regulation entries, please.

Posted by: Davi Ottenheimer at April 1, 2005 01:20 AM

My personal experience with CCTV...

I parked my motorcycle in possibly the most secure location in the whole of Hitchin... In clear view of not one, not two, but three CCTV cameras; within an arms length of the Corn Exchange door staff and a busy area of town.

On my return, approximately 30 minutes after closing (by which point the door staff from the pub had gone and it had qot a bit quieter) my bike had gone.

[It was probably also the only time I didn't use an additional lock]

I reported the incident to the police, who did nothing - not even check the CCTV tapes! (I know this because I have a contact in the council, who operate the cameras [and therefore tapes]).

...if the police are not going to use the resources available to them (probably because they are out hassling motorists) why bother?

Posted by: Ben Smyth at April 1, 2005 05:38 AM

OT [very OT] On a separate note, you may be interested in Steve Bellovin's security panacea -

Posted by: Ben Smyth at April 1, 2005 05:39 AM

@Watching Them, Watching Us
I do believe that under british law warning signs are REQUIRED to be posted in order for the evidence to be admissable in court, not having those signs makes them even more pointless and a waste of money, I believe they work in certain instances, in certain limited ranges, but plasting them over Brixton high road does bugger all to lower crime , the angle of some of them requires the criminal to actually have to look up in the direction of a camera to get a good facial, i mean whos going to do that?

Increasing the police force is one option, but that doesnt give people much assurance either, as alot of us are loosing faith in the force

Posted by: Phoenix at April 1, 2005 06:43 AM

Very often the example found here remind me on that famous machine that goes 'ping' from the Monty Python film "The Meaning Of Life".

It seems that a lot of technological "solutions" are machines that go 'ping'. They don't necesserely solve anything, but there's a lot of 'political' motivation to buy them.

Posted by: AC at April 1, 2005 09:11 AM


I am not a car driver I preffer to ride my push bike. Also I do not know if you are from the UK or not, but the traffic laws etc are somewhat odd in the UK.

First off in the UK there are allready quite effective messures in place for collecting unpaid "road fund" which the tax is often known as and is around 300USD/year.

Basically if you are the "registered owner" of a car and you have not paid up you get a court summons after about 1.5 months. There are also other arangments for imprisonment etc.

Also you pay your "Road Fund" to the UK Government (central not regional/local) who then spend it on what they see fit (Generally not roads accident prevention or Health or other related activities).

I looked back to some of the recent quotes about these new cammerers given by the press, and it would appear they are for directly applying "extra fines" which would have the revenue split between the cammer operators ( the likes of Capita etc) and the authority (either police or regeional/local government). These Local authorities then spend the money on what they like. On a side note Capita who run the congestion charging system in London have been subject to many many (upheld) complaints about the way they extort money out of motorists who have paid etc.

SO you get fined by central government if you do not pay your road fund, and get additional fines by the local government if you drive your car in their area.

I have also seen reports on studies that show that "non physical" traffic pasivation systems not only do not work, they actually increase the likley hood of accidents. This is because drivers get to know where the cammeras are and use excessive speed between them then brake suddenly to reduce speed where they are. The results of this lunatic behaviour are fairly obvious and have been reported in the press. Also that some people simply regard the fines as a normal business expense so they do not act as a deterant.

Additionally the tab for road accidents is usually picked up by the health service in terms of immediate (and often longterm) care.

SO I still stand by my original comment that the cammerers (being a non physical traffic control system) are just a money raising system.

If anybody has evidence to the contry I would be very happy to see it.

Posted by: clive robinson at April 1, 2005 09:40 AM

Camera survelliance needs money to work.
Hollywood has tons of it.
Problem solved....

Posted by: Diego Zenizo at April 1, 2005 09:49 AM

@Ottenhemer, you wrote:

"What you have happened upon is an opporuntity to make Surveillance technology more effective in reducing crime."

The British study found that cameras didn't reduce crime in 13 of 14 areas tracked over time. We can debate whether the glass is 13/14ths empty or 1/14th full, but on the whole, I think it's hard to argue for continuing to waste resources on generalized camera surveillance in public areas.

Also, just to have said it, the opinions expressed on my blog are my own, not any ACLU policy unless expressly stated. The post represented my personal musings trying to reconcile the results of the British survey with Dennis' arguments. I proposed an untested, maybe untestable hypothesis to explain the study results, but wouldn't want anyone to draw implications from that about ACLU's official stance. Best,

Posted by: Scott at April 1, 2005 04:19 PM

Why would we believe that surveillance cameras would deter criminals really?

You have to understand the way criminals think. Most people who commit a crime do not believe they will ever be caught however lacking in logic this sounds. They also tend to be more impulsive and lack the ability to really think things through.
Convience store robers tend to be after some quick cash to meet the needs of an addiction so they are even less smart about their crimes.

Do cameras increase arrest rates?
For the careless criminal they would seem to make good evidence.

The problem with survelance cameras is that they are a tertiary response to the problem, they come to late in the chain of events. The best they can be used for is to try to catch the criminal not prevent or intervene.

Posted by: Laura Jean at April 1, 2005 05:39 PM

"I reported the incident to the police, who did nothing - not even check the CCTV tapes! (I know this because I have a contact in the council, who operate the cameras [and therefore tapes])."

Aw, c'mon! Just how often do police do much about stolen vehicles? They take the details, but if there's nothing unusual - like there's a kid or a briefcase full of diamonds inside - that's about it.

I realise you'd like the cops to drop everything and get back your motorbike quicksmart, but fair suck, mate!

Now, if you had been murdered in full view of the cameras, you could expect some serious action.

Posted by: Peter at April 2, 2005 01:38 AM


Point taken, but there was a spate of bike thefts going on at the time - hence you'd expect some organised outfit.

Posted by: Ben Smyth at April 2, 2005 05:19 AM


I'd expect "some serious action" to a murder, cameras or not.

I believe the point is that the cameras were put in place to prevent lesser crimes (like bike theft), not on the of chance that they catch a murder.

The camera system failed to prevent the theft and was not used to recover it.

Either the system failed, or people were lied to about the reason it was put in.

Posted by: Thomas Sprinkmeier at April 2, 2005 06:58 AM

Stealing a bike and murder are two extremes of the crime spectrum. I seriously doubt that these particular cameras were touted as being able to eliminate minor crime. Crimes that very few police departments would do much about anyway, not because they don't care, but because they have more serious crimes to investigate.

I suggest that if a police department has time to chase down security camera tapes of a minor crime like this, then the community probably doesn't need much in the way of security anyway.

But if the crime had been more serious, say robbery or assault or rape, then action would likely have been taken to examine the tapes, not just for possible identification of the offenders but to determine what had happened.

It's not the cameras that determine if action should be taken, nor even the people controlling the cameras. It's the people who are going to have to investigate the crime, make an arrest and prosecute the offender who determine if action will be taken.

Posted by: Peter at April 2, 2005 01:27 PM

As I see it, the point of this article (which I agree with) is that cameras by themselves don't deter crime. There has to be somebody watching the camera, or at least scanning through them often enough that a crime is likely to be seen, and the watcher has to have the ability and willingness to send help to the scene immediately. (A worthwhile enhancement would be a mike that detects specific sounds such as a scream and switches the scanning person's view to its source.)

If this level of service is not going to be provided, then I'd put up signs warning people that they're responsible for their own safety and advising them to carry guns (if allowed there).

Whether cameras are unacceptable invasions of privacy is another question. I feel that even when used in public places, where people's coming and going are public information, if there are so many cameras (and good enough software for viewing what they've seen) that you can follow a person's movements from place to place, then doing so is in effect "stalking". Doing so should be prohibited for non-police (outside of their own private property) and should require a warrant for police.

Posted by: John David Galt at April 2, 2005 02:14 PM

You disable the things with a shotgun or the tools you have. Wear a mask and the camera is useless. The camera is $600.00 and the mask is $1.00 at the thrift store. The security people are sitting there looking at footage a week after the crime is over and done with. More dumb world domination schemes, so put cameras everywhere.

Posted by: Jim at April 2, 2005 10:43 PM

"The camera is $600.00 and the mask is $1.00 at the thrift store. The security people are sitting there looking at footage a week after the crime is over and done with. "

What's the problem? The camera isn't going to solve the crime. But seeing how a criminal acts, even a week after it happens, provides a lot of information. Enough for modus operandi to be noted and perhaps linked to somebody already known.

A security camera is just another tool for crimefighting. Not a magic bullet.

Posted by: Peter at April 3, 2005 01:58 PM


I did live in the uk until recently, so I understand the rules.

You said,

"SO you get fined by central government if you do not pay your road fund, and get additional fines by the local government if you drive your car in their area."

I'm not sure what you are complaining about... OK, if you believe the press (and why wouldn't you) these are purely revenue raising cameras for people who haven't paid their road tax, what's the issue ?

Fair enough if you've paid and they say you haven't ... complain.

Fair enough if your car is stolen (kept past the renewal date) and you get a fine ... complain.

If i hire a dvd from blockbusters and don't return it, they will fine me. If i hire a book from the library and don't return it, they will keep adding fines onto the account until i return it and pay off the fines.

So why should life be magically different for motorists ?

Posted by: Anonymous at April 3, 2005 08:32 PM


As I indicated I am not a motorist (for various reasons), however I have two main objections,

The first is the cost of such a system compaired to it's extreamly low return rate (Look into the London Congestion charge for an example of this). The only people who realy benifit are the private companies that run the systems.

The second is mission creep, after the expensive system has been installed and found to be nolonger effective (criminals work by natural selection which is why technical only security systems initialy work then fail), they have to find a new use (such as road tolls) to justify extracting vast quantaties of money out of people for carrying on their everyday activities (see my earlier post with regards to micro chips in dustbins).

The result of this sort of stupidity is that a percentage of the population will always find ways around these systems and usually at the expense of everybody else. The goverment solution is to get more and more high tech solutions which are all going to fail eventually as people learn to adapt to them... The only people to benifit are the private companies who supply the systems.

If you want security the solution you put in place needs to be as flexable and adaptable as the criminals (ie human beings). Then support them correctly with adaptive technology to give them a slight edge. Not the other way around, it is doomed by the proceses of adaption and natural selection by the criminals who will always end up with the edge over the police.

An example of how to make a technology like cammeras flexable is to put them in rented unmarked cars/vans/etc and move them around so finding them is very difficult, therefore the ability to adapt by the criminals is vastly reduced.

It is after all a game of Cat and mouse, and the cats should always behave like cats not mice.

Posted by: clive robinson at April 4, 2005 04:30 AM

I did read the original paper, as I find that newspaper reports of research are rarely accurate. On the basis of this reading, I have to say that the report which characterises this as failing in all but one case out of 14 is not accurate.

For a start, although there were 14 projects, they did ~75 studies within these, depending how you count them. Prof. Gill found that in many cases it was not possible to arrive at a definite conclusion due to the many difficulties that can be associated with such studies. This was not necessarily because no effect was seen nor necessarily because the effect was small; for example in one case vehicle crime was reduced 41% from 1641 to 972, but this apparently huge result was statistically insignificant because the background rate in that region fluctuated by very wide margins. If a study can't distinguish between a genuine 41% reduction and normal variations then the only way to obtain useful information in that study would be to maintain observations for a much longer period than their funding allowed. In another case a fall in vehicle crime of 42% _was_ statistically significant, but still could not be counted as changes in parking regulations had altered the manner of parking vehicles in the area, so the results where not directly comparable. Many other examples were confounded by the fact that cameras were installed at the same time as other crime-reduction projects. Altogether only 16 of the 75 studies returned usable data, indicating overwhelmingly that this study was far too short to be useful. Of those 16, 6 studies in 3 projects showed a definite positive effect, which is a good deal better than 1 in 14.

Among the remaining 10 we have the difficulty of studies in which a reported crime rate increased, but it was the opinion of the authors that this was due to improved detection or reporting of an existing crime rate (mainly shoplifting and public disorder near pubs), usually due to other projects installed at the same time. Again, more research is required to really understand these results.

There were also two studies in which there was a definite increase in crime, but in one of those cases the increase consisted largely of attempts to vandalise the cameras, at the same time as the burglary rate plummeted; while in the other, the camera setup was a new experimental system which was found to be ineffective.

It is also notable that there seems to be considerable variation according to the care in design and planning of a system, ranging from the Borough experiment which was completely useless, to the carefully planned Project Hawkeye which resulted in a statistically significant 73% reduction in its targeted crime.

Overall, it seems to me that the principle results of this study are:
* that it was too short and more work is required;
* that in the cases where a definite conclusion can be reached, CCTV produced a useful effect in a little over one third of studies;
* to the extent cameras are effective, they are more effective in high crime areas; and
* there is considerable difference between carefully planned and carelessly planned or poorly maintained systems.

Posted by: Roger at April 4, 2005 11:30 AM

... not to mention that who knows who is on the other side of the camera lens? Sure it may be intended for a security team, but there are plenty of examples where attackers have complete access to a surveillance system without being discovered in a timely fashion. The more complex a system, the more places there are to hide. (e.g. wireless systems, internet cameras)

Israel Torres

Posted by: Israel Torres at April 4, 2005 03:19 PM

"Overall, it seems to me that the principle results of this study are:
* that it was too short and more work is required;"

Isn't that the result of every study?

Posted by: Thomas Sprinkmeier at April 4, 2005 06:51 PM

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