Schneier on Security
A blog covering security and security technology.
« Anonymity and the Tor Network |
| More on the German Terrorist Plot »
September 20, 2007
London's Security Cameras Don't Help
Interesting article. London's 10,000 security cameras don't reduce crime:
A comparison of the number of cameras in each London borough with the proportion of crimes solved there found that police are no more likely to catch offenders in areas with hundreds of cameras than in those with hardly any.
In fact, four out of five of the boroughs with the most cameras have a record of solving crime that is below average.
EDITED TO ADD (10/11): This is a follow-up to a 2005 article.
Posted on September 20, 2007 at 2:03 PM
• 35 Comments
To receive these entries once a month by e-mail, sign up for the Crypto-Gram Newsletter.
"In fact, four out of five of the boroughs with the most cameras have a record of solving crime that is below average."
All this suggests is that those boroughs have a lot of crime, and as a result extra security cameras were installed. It would be unwise to judge the efficacy of security cameras based on these statistics alone, since surely the very reason the cameras are there is because those areas are already predisposed to crime?
Unfortunately, the lesson our masters will draw from this article is that we need more intrusive and draconian monitoring of the proles.
@Random: So you're saying that spending money on cameras is justifiable solely based on an area being "predisposed to crime"? I'd bet you could spend the money more wisely and actually reduce crime...
True, in fact it is hard to find any single control that automatically reduces crime.
The article does not say to me that cameras don't reduce crime but rather that they could be more effectively deployed and managed. The article points out that the data only refers to state managed cameras, and that the verdict is still out:
"Although CCTV has its place, it is not the only solution in preventing or detecting crime."
Shame they didn't elaborate on the "place" comment.
The deviation between locations is lacking detail. Need to get a copy of the report to make sense of this:
"Hackney has the most cameras - 1,484 - and has a better-than-average clearup rate of 22.2 per cent.
By contrast, boroughs such as Kensington and Chelsea, Sutton and Waltham Forest have fewer than 100 cameras each yet they still have clear-up rates of around 20 per cent."
Types of crime, number of detectives per incident, etc. all must play a factor.
Perhaps the question instead is whether Hackney's rate would be lower if you took the cameras away. Or, from the opposite angle, did something else change in the places with few cameras? Lighting, for example...
"A report by the criminal justice charity Nacro in 2002 concluded that the money spent on cameras would be better used on street lighting, which has been shown to cut crime by up to 20 per cent."
Yeah. Ideally I'd like to know:
1) Did adding cameras have any causal relationship with the rate at which crimes are solved?
2) Did adding cameras have any causal relationship with the rate at which crimes are committed.
Let's see if that freakanomics guy can analyze the data for us....
Funny, it looks to me as if the choice to do a spatial analysis (cross-borough rates of solved crimes) instead of a chronological analysis (rate of crime-solving in each borough as a function of time/number of deployed cameras) introduces all kinds of unnecessary factors that require control (background crime rate, differential lighting, etc., as already pointed out above).
Why'd they do it that way? Wouldn't you like to know whether cameras increased crime-solving in each borough, rather than whether crime-solving was higher in boroughs with more cameras? I would.
Was there an original claim that the cameras had anything to do with crime prevention, detection, or investigation?
Me too, Carlo. After all, the county with the highest median income in the U.S. has a much higher crime rate than the North Pole, which has a median income of $0. Therefore, we can say that higher income correlates to higher crime rates...
Bruce, that fact-light article does not support your conclusion. To show that cameras do not help, you need to compare statistics for the same place before and after cameras were introduced. The article compares the resolution of crimes in areas differing concentrations of cameras to a mythical "average crime solving rate". Since crime is known to vary strongly by area anyway, the conclusions are void.
The problem is the lack of any serious attempt to enforce the law. The London police (especially in these "high-crime" areas) don't bother to investigate bicycle thefts, or burglary. If you report a bicycle theft, the police will merely tell you that you should have used a better lock. If you're a homeowner and your burglar-alarm goes off, the sum total of police activity will be to caution you for causing a nuisance by having a loud burglar alarm. (No, I am NOT joking. This is NOT satire. This is fact.)
The police see their job as levying draconian fines for minor traffic offences, and smashing down people's doors in the middle of the night if they're suspected of possessing substances that the government has declared to be illegal.
Given these attitudes by the police, no crime-prevention measures will work (not even better bicycle locks: see
Whether the root of the problem lies with senior police officers or with the politicians who have ultimate control, I don't pretend to know, but it has to be one of those.
Comparisons over time are useful, but keep in mind that crime rates vary randomly and cameras (or other solutions) are most likely to be imposed when crime rates are at a peak. So a decrease would be expected just do to random variation. See: "Reforms as experiments." Am Psychol 24: 409-429
Well, yes, but keep in mind that what is being tested here is not the correlation of camera deployment with crime rates, but rather with crime-solving rates.
There probably is an inverse relation of crime-solving to crime (due to finite law-enforcement resources), but I would be very surprised if it were a very strong effect, so I would not expect camera deployments at crime-rate peaks to constitute strong selection effects, capable of producing spurious increases in crime-solving rates.
"...police are no more likely to catch offenders in areas with hundreds of cameras than in those with hardly any."
London newspapers seem to have no idea how to report meaningful statistics, especially when it comes to crime.
Interesting, but more data is needed to come to any conclusions. For example:
- How many crimes are reported in each area?
- How many police work in each area?
Security cameras were installed to increase
security and reduce overall crime as well
as increaseing the efficiency of clearing up
It is tempting to now argue that the
successrate is also dependent on how
many police work took place and
how many crimes were reported in each
But by doing so we are actualy admitting
what we always knew, namely that those
cameras alone would not change anything.
To reduce crime you need good police work,
much more than cameras. ... So why did you
install those cameras again? ;)
Of course they don't help.
But where are the pictures from 2005-07-07 and 2005-07-21? Since this happened on the tube, there must be more than the one we have been shown.
Crime rates/crime solving rates will fluctuate with time (in mysterious, not random, ways) which I am sure is why they compared places with cameras to places without cameras.
Location is probably a harder variable to control for, but comparing before cameras to after cameras isn't a problem free solution.
actual not that interesting an article, i'm afraid.
where's the proper analysis.
what is it that makes those areas have more cameras?
what are the crimes in the different areas, are the crimes different between the areas of high and low surveillance?
Do the introduction of cameras change the type of crime. Are there trends of crime changing as more cameras are introduced.
Percentages are one thing but what are the actual figures.
And glaringly missing are the figures over time. ie How do the percentages of solved crimes change as more cameras are introduced. Did they stay the same even when more cameras where introduced.
What are the national averages of solving crimes for all the particular crimes in each area.
please don't promote half-assed reports like this.
Is there any logical connection between number of CCTVs and crime
What definition of crime or what crime are these people looking at?
Can CCTVs help in solving all crimes?
This is a silly unimformed article
I grew up in Cambridge UK and witnessed the effect of installing CCTV in the town centre (or, at least, the immediate effect on crime). It basically moved the drunken 11pm fights around the corner, to where there was no CCTV. However, it DID help to define an area around the cameras which was relatively crime-free, much as street lighting does. Whether this is still true now that kids all wear hoodies, I don't know.
The police in London have reached levels of inneficiency where statistics become meaningless.
Crimes are reported soley because you need a slip of paper from the police before you can make an insurance claim.
If you are not/underinsured or if you think the claim is less than the amount the insurance company will hike up your next premium for making a claim you are not going to bother making an insurance claim and therefore you are not going to bother reporting the crime.
Similarly violent crime gets reported automaticly if you end up in the hospital emergency room, if you dont end up there you probably wont bother reporting the crime as the chances of the police doing anything other than reluctantly "recording" are almost nil.
There is such a disparity between official police statistics and the results of surveys of the general public as to render the official statistics invalid.
Londoners can do nothing about this situation. The police force is controlled and largly funded by central government who regard the Met as thier own personal security force. The influence a Londoner can bring to bear is thier vote in a General election if they happen to live in one of the 5 out of twenty constituencies which are not "safe" seats.
England should really give democracy a chance no matter how inconvient this is for the politicians.
Agree with Carlo Graziani, There doesn't seem to be a decent control for the study.
Kensington and Chelsea and Hackney have very different social classes of people living there. This should be taken into account.
I think supersnail summed it up nicely.
Also according to:
the UK's police force spends 80% of its time filling in paperwork.
( One minor point - unlike Wales, Scotland or Northern Ireland who have separate assemblies - England itself can't experiment with democracy! )
Australia 'cracked top-secret US jet fighter codes'
Is the similar "key sharing problem" the reason for "friendly fire" between US and British aircrafts during Iraq company?
The real problem in the UK is that while we spend millions on high res cameras that are being placed on every major road to track our movements, the cameras we depend on for street crime appear to be the cheapest, nastiest variety available as demonstrated by the crap quality pictures on wanted posters (crimewatch etc). Criminals are not stupid and they know a low res picture is of low risk to them, not to mention avoiding the static cameras in the first place.
Anyone that thinks cameras as we have them now solve and deter crime in any meaningful way is as stupid as the minority of criminals they catch, leading to prosecution.
Police patrolling the streets in an unpredictable way and given the power to actually do something with offenders to prevent re-occurance is whats needed.
"...Although CCTV has its place, it is not the only solution in preventing or detecting crime..." I cannot see a relation with a crime-solving rate... detering is not solving. Give me no crime and I will be perfectly happy with a 0% solving rate
The article doesn't mention how often camera tapes were used as part of an investigation, and how often (or not) the tapes contributed evidence that holds up in court.
Our city is planning on spending $3.5 million installing more cameras. This will save the city money, since they can get rid of more police officers with the cameras replacing patrols. The last city political wizards got rid of the horses, because the mounted patrol wasn't cost effective. Now it's a big business because horses are good for the city or the mall. No gasoline!
"The business originally began as Western Adventures, providing hayrides and barbecues for fraternities and sororities on campus in Las Cruces, New Mexico. From this humble beginning the company grew and began to provide Santa arrivals for shopping malls. This insight into the shopping center industry gave birth to Alpha & Omega, a mounted patrol security company for shopping centers."
Screw the cameras, bring in more horses.
Installing security cameras will have an initial effect which fades with time. You tube offers thousands of caught-in-the-act criminals who know the cameras are there and could simply care less. The removal or reduction of police officers caused by camera installations, actually causes an increase in crime, not a decrease. A camera that witnesses a crime, sits there and does nothing, offers no immediate physical assistance, and it's effectiveness is based upon whether anyone is actually watching THAT camera at THAT time. A live police officer that witnesses the same crime, could physically respond immediately and actually provide a real service. What this survey should be considering: What are the numbers of crimes committed in front of these cameras that goes unnoticed. Of the events that are noticed, what are the delay times to get an officer to that scene, and, of the noticed/responded to crimes, how many of those were solved as a DIRECT RESULT of the video images.
Of course, the cameras do help. In fact, they help immensely. To fatten bank accounts of politically-connected purveyors of "security", and to make politicos appear "tough on crime".
Big brother is watching but we can't really justify it yet... hang on.
Simon asks if the cameras were intenede to solve crime our be used in the investigation of crime, apparently there is some other purpose? wait until its all synthesized, the rfid built into shoes and pants, the cellphone gps, the totalitarian phone taps, Choice Point files, the cameras, and your highschool permanent record, All accessed by the UPC 714 tattooed in radium on your neck.
Schneier.com is a personal website. Opinions expressed are not necessarily those of BT.