Entries Tagged "cost-benefit analysis"

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Amber Alerts As Security Theater

Interesting analysis:

Since its birth 12 years ago after a fatal kidnapping in Texas, Amber Alert has quickly become one of the best-known tools in the national law enforcement arsenal. The warnings are familiar to anyone who watches cable TV news, especially during the summer, when the drumbeat of abduction stories seems to increase. Last year, 227 alerts were issued nationwide, each galvanizing interest in the local community and flooding police with tips. While the particulars of the state systems differ, the goal is the same: to disperse news of a kidnapping as widely and quickly as possible, in the hope that someone will spot the kidnapper before a child is harmed.

The program’s champions say that its successes have been dramatic. According to the National Center for Missing and Exploited Children, more than 400 children have been saved by Amber Alerts. Of the 17 children Massachusetts has issued alerts on since it created its system in 2003, all have been safely returned.

These are encouraging statistics—but also deeply misleading, according to some of the only outside scholars to examine the system in depth. In the first independent study of whether Amber Alerts work, a team led by University of Nevada criminologist Timothy Griffin looked at hundreds of abduction cases between 2003 and 2006 and found that Amber Alerts—for all their urgency and drama—actually accomplish little. In most cases where they were issued, Griffin found, Amber Alerts played no role in the eventual return of abducted children. Their successes were generally in child custody fights that didn’t pose a risk to the child. And in those rare instances where kidnappers did intend to rape or kill the child, Amber Alerts usually failed to save lives.

Posted on August 11, 2008 at 7:59 AM • View Comments

Cost/Benefit Analysis of Airline Security

This report, “Assessing the risks, costs and benefits of United States aviation security measures” by Mark Stewart and John Mueller, is excellent reading:

The United States Office of Management and Budget has recommended the use of cost-benefit assessment for all proposed federal regulations. Since 9/11 government agencies in Australia, United States, Canada, Europe and elsewhere have devoted much effort and expenditure to attempt to ensure that a 9/11 type attack involving hijacked aircraft is not repeated. This effort has come at considerable cost, running in excess of US$6 billion per year for the United States Transportation Security Administration (TSA) alone. In particular, significant expenditure has been dedicated to two aviation security measures aimed at preventing terrorists from hijacking and crashing an aircraft into buildings and other infrastructure: (i) Hardened cockpit doors and (ii) Federal Air Marshal Service. These two security measures cost the United States government and the airlines nearly $1 billion per year. This paper seeks to discover whether aviation security measures are cost-effective by considering their effectiveness, their cost and expected lives saved as a result of such expenditure. An assessment of the Federal Air Marshal Service suggests that the annual cost is $180 million per life saved. This is greatly in excess of the regulatory safety goal of $1-$10 million per life saved. As such, the air marshal program would seem to fail a cost-benefit analysis. In addition, the opportunity cost of these expenditures is considerable, and it is highly likely that far more lives would have been saved if the money had been invested instead in a wide range of more cost-effective risk mitigation programs. On the other hand, hardening of cockpit doors has an annual cost of only $800,000 per life saved, showing that this is a cost-effective security measure.

From the body:

Hardening cockpit doors has the highest risk reduction (16.67%) at lowest additional cost of $40 million. On the other hand, the Federal Air Marshal Service costs $900 million pa but reduces risk by only 1.67%. The Federal Air Marshal Service may be more cost-effective if it is able to show extra benefit over the cheaper measure of hardening cockpit doors. However, the Federal Air Marshal Service seems to have significantly less benefit which means that hardening cockpit doors is the more cost-effective measure.

Cost-benefit analysis is definitely the way to look at these security measures. It’s hard for people to do, because it requires putting a dollar value on a human life—something we can’t possibly do with our own. But as a society, it is something we do again and again: when we raise or lower speed limits, when we ban a certain pesticide, when we enact building codes. Insurance companies do it all the time. We do it implicitly, because we can’t talk about it explicitly. I think there is considerable value in talking about it.

(Note the table on page 5 of the report, which lists the cost per lives saved for a variety of safety and security measures.)

The final paper will eventually be published in the Journal of Transportation Security. I never even knew there was such a thing.

EDITED TO ADD (8/13): New York Times op-ed on the subject.

Posted on July 21, 2008 at 5:53 AM • View Comments

Homeland Security Cost-Benefit Analysis

This is an excellent paper by Ohio State political science professor John Mueller. Titled “The Quixotic Quest for Invulnerability: Assessing the Costs, Benefits, and Probabilities of Protecting the Homeland,” it lays out some common send premises and policy implications.

The premises:

1. The number of potential terrorist targets is essentially infinite.

2. The probability that any individual target will be attacked is essentially zero.

3. If one potential target happens to enjoy a degree of protection, the agile terrorist usually can readily move on to another one.

4. Most targets are “vulnerable” in that it is not very difficult to damage them, but invulnerable in that they can be rebuilt in fairly short order and at tolerable expense.

5. It is essentially impossible to make a very wide variety of potential terrorist targets invulnerable except by completely closing them down.

The policy implications:

1. Any protective policy should be compared to a “null case”: do nothing, and use the money saved to rebuild and to compensate any victims.

2. Abandon any effort to imagine a terrorist target list.

3. Consider negative effects of protection measures: not only direct cost, but inconvenience, enhancement of fear, negative economic impacts, reduction of liberties.

4. Consider the opportunity costs, the tradeoffs, of protection measures.

Here’s the abstract:

This paper attempts to set out some general parameters for coming to grips with a central homeland security concern: the effort to make potential targets invulnerable, or at least notably less vulnerable, to terrorist attack. It argues that protection makes sense only when protection is feasible for an entire class of potential targets and when the destruction of something in that target set would have quite large physical, economic, psychological, and/or political consequences. There are a very large number of potential targets where protection is essentially a waste of resources and a much more limited one where it may be effective.

The whole paper is worth reading.

Posted on July 17, 2008 at 6:43 AM • View Comments

CCTV Cameras

Pervasive security cameras don’t substantially reduce crime. There are exceptions, of course, and that’s what gets the press. Most famously, CCTV cameras helped catch James Bulger’s murderers in 1993. And earlier this year, they helped convict Steve Wright of murdering five women in the Ipswich area. But these are the well-publicised exceptions. Overall, CCTV cameras aren’t very effective.

This fact has been demonstrated again and again: by a comprehensive study for the Home Office in 2005, by several studies in the US, and again with new data announced last month by New Scotland Yard. They actually solve very few crimes, and their deterrent effect is minimal.

Conventional wisdom predicts the opposite. But if that were true, then camera-happy London, with something like 500,000, would be the safest city on the planet. It isn’t, of course, because of technological limitations of cameras, organisational limitations of police and the adaptive abilities of criminals.

To some, it’s comforting to imagine vigilant police monitoring every camera, but the truth is very different. Most CCTV footage is never looked at until well after a crime is committed. When it is examined, it’s very common for the viewers not to identify suspects. Lighting is bad and images are grainy, and criminals tend not to stare helpfully at the lens. Cameras break far too often. The best camera systems can still be thwarted by sunglasses or hats. Even when they afford quick identification—think of the 2005 London transport bombers and the 9/11 terrorists—police are often able to identify suspects without the cameras. Cameras afford a false sense of security, encouraging laziness when we need police to be vigilant.

The solution isn’t for police to watch the cameras. Unlike an officer walking the street, cameras only look in particular directions at particular locations. Criminals know this, and can easily adapt by moving their crimes to someplace not watched by a camera—and there will always be such places. Additionally, while a police officer on the street can respond to a crime in progress, the same officer in front of a CCTV screen can only dispatch another officer to arrive much later. By their very nature, cameras result in underused and misallocated police resources.

Cameras aren’t completely ineffective, of course. In certain circumstances, they’re effective in reducing crime in enclosed areas with minimal foot traffic. Combined with adequate lighting, they substantially reduce both personal attacks and auto-related crime in car parks. And from some perspectives, simply moving crime around is good enough. If a local Tesco installs cameras in its store, and a robber targets the store next door as a result, that’s money well spent by Tesco. But it doesn’t reduce the overall crime rate, so is a waste of money to the township.

But the question really isn’t whether cameras reduce crime; the question is whether they’re worth it. And given their cost (£500 m in the past 10 years), their limited effectiveness, the potential for abuse (spying on naked women in their own homes, sharing nude images, selling best-of videos, and even spying on national politicians) and their Orwellian effects on privacy and civil liberties, most of the time they’re not. The funds spent on CCTV cameras would be far better spent on hiring experienced police officers.

We live in a unique time in our society: the cameras are everywhere, and we can still see them. Ten years ago, cameras were much rarer than they are today. And in 10 years, they’ll be so small you won’t even notice them. Already, companies like L-1 Security Solutions are developing police-state CCTV surveillance technologies like facial recognition for China, technology that will find their way into countries like the UK. The time to address appropriate limits on this technology is before the cameras fade from notice.

This essay was previously published in The Guardian.

EDITED TO ADD (7/3): A rebuttal.

EDITED TO ADD (7/6): More commentary.

EDITED TO ADD (7/9): Another good survey article, and commentary.

Posted on June 26, 2008 at 1:18 PM • View Comments

LifeLock and Identity Theft

LifeLock, one of the companies that offers identity-theft protection in the United States, has been taking quite a beating recently. They’re being sued by credit bureaus, competitors and lawyers in several states that are launching class action lawsuits. And the stories in the media … it’s like a piranha feeding frenzy.

There are also a lot of errors and misconceptions. With its aggressive advertising campaign and a CEO who publishes his Social Security number and dares people to steal his identity—Todd Davis, 457-55-5462—LifeLock is a company that’s easy to hate. But the company’s story has some interesting security lessons, and it’s worth understanding in some detail.

In December 2003, as part of the Fair and Accurate Credit Transactions Act, or Facta, credit bureaus were forced to allow you to put a fraud alert on their credit reports, requiring lenders to verify your identity before issuing a credit card in your name. This alert is temporary, and expires after 90 days. Several companies have sprung up—LifeLock, Debix, LoudSiren, TrustedID—that automatically renew these alerts and effectively make them permanent.

This service pisses off the credit bureaus and their financial customers. The reason lenders don’t routinely verify your identity before issuing you credit is that it takes time, costs money and is one more hurdle between you and another credit card. (Buy, buy, buy—it’s the American way.) So in the eyes of credit bureaus, LifeLock’s customers are inferior goods; selling their data isn’t as valuable. LifeLock also opts its customers out of pre-approved credit card offers, further making them less valuable in the eyes of credit bureaus.

And, so began a smear campaign on the part of the credit bureaus. You can read their points of view in this New York Times article, written by a reporter who didn’t do much more than regurgitate their talking points. And the class action lawsuits have piled on, accusing LifeLock of deceptive business practices, fraudulent advertising and so on. The biggest smear is that LifeLock didn’t even protect Todd Davis, and that his identity was allegedly stolen.

It wasn’t. Someone in Texas used Davis’s SSN to get a $500 advance against his paycheck. It worked because the loan operation didn’t check with any of the credit bureaus before approving the loan—perfectly reasonable for an amount this small. The payday-loan operation called Davis to collect, and LifeLock cleared up the problem. His credit report remains spotless.

The Experian credit bureau’s lawsuit basically claims that fraud alerts are only for people who have been victims of identity theft. This seems spurious; the text of the law states that anyone “who asserts a good faith suspicion that the consumer has been or is about to become a victim of fraud or related crime” can request a fraud alert. It seems to me that includes anybody who has ever received one of those notices about their financial details being lost or stolen, which is everybody.

As to deceptive business practices and fraudulent advertising—those just seem like class action lawyers piling on. LifeLock’s aggressive fear-based marketing doesn’t seem any worse than a lot of other similar advertising campaigns. My guess is that the class action lawsuits won’t go anywhere.

In reality, forcing lenders to verify identity before issuing credit is exactly the sort of thing we need to do to fight identity theft. Basically, there are two ways to deal with identity theft: Make personal information harder to steal, and make stolen personal information harder to use. We all know the former doesn’t work, so that leaves the latter. If Congress wanted to solve the problem for real, one of the things it would do is make fraud alerts permanent for everybody. But the credit industry’s lobbyists would never allow that.

LifeLock does a bunch of other clever things. They monitor the national address database, and alert you if your address changes. They look for your credit and debit card numbers on hacker and criminal websites and such, and assist you in getting a new number if they see it. They have a million-dollar service guarantee—for complicated legal reasons, they can’t call it insurance—to help you recover if your identity is ever stolen.

But even with all of this, I am not a LifeLock customer. At $120 a year, it’s just not worth it. You wouldn’t know it from the press attention, but dealing with identity theft has become easier and more routine. Sure, it’s a pervasive problem. The Federal Trade Commission reported that 8.3 million Americans were identity-theft victims in 2005. But that includes things like someone stealing your credit card and using it, something that rarely costs you any money and that LifeLock doesn’t protect against. New account fraud is much less common, affecting 1.8 million Americans per year, or 0.8 percent of the adult population. The FTC hasn’t published detailed numbers for 2006 or 2007, but the rate seems to be declining.

New card fraud is also not very damaging. The median amount of fraud the thief commits is $1,350, but you’re not liable for that. Some spectacularly horrible identity-theft stories notwithstanding, the financial industry is pretty good at quickly cleaning up the mess. The victim’s median out-of-pocket cost for new account fraud is only $40, plus ten hours of grief to clean up the problem. Even assuming your time is worth $100 an hour, LifeLock isn’t worth more than $8 a year.

And it’s hard to get any data on how effective LifeLock really is. They’ve been in business three years and have about a million customers, but most of them have joined up in the last year. They’ve paid out on their service guarantee 113 times, but a lot of those were for things that happened before their customers became customers. (It was easier to pay than argue, I assume.) But they don’t know how often the fraud alerts actually catch an identity thief in the act. My guess is that it’s less than the 0.8 percent fraud rate above.

LifeLock’s business model is based more on the fear of identity theft than the actual risk.

It’s pretty ironic of the credit bureaus to attack LifeLock on its marketing practices, since they know all about profiting from the fear of identity theft. Facta also forced the credit bureaus to give Americans a free credit report once a year upon request. Through deceptive marketing techniques, they’ve turned this requirement into a multimillion-dollar business.

Get LifeLock if you want, or one of its competitors if you prefer. But remember that you can do most of what these companies do yourself. You can put a fraud alert on your own account, but you have to remember to renew it every three months. You can also put a credit freeze on your account, which is more work for the average consumer but more effective if you’re a privacy wonk—and the rules differ by state. And maybe someday Congress will do the right thing and put LifeLock out of business by forcing lenders to verify identity every time they issue credit in someone’s name.

This essay originally appeared in Wired.com.

Posted on June 17, 2008 at 6:51 AM • View Comments

Dan Geer on Security, Monoculture, Metrics, Evolution, Etc.

Here is the text and video of Dan Geer’s remarks at Source Boston 2008, basically a L0pht reunion with friends.

At the end of the day, however, we are facing a much bigger, more metaphysical question than the ones I have so far posed. That I can pose many others is of no consequence; either you are sick of them by now or you are scribbling down your own as I speak. The bigger question is this—how much security do we want?

A world without failure is a world without freedom. A world without the possibility of sin is a world without the possibility of righteousness. A world without the possibility of crime is a world where you cannot prove you are not a criminal. A technology that can give you everything you want is a technology that can take away everything that you have. At some point, real soon now, some of us security geeks will have to say that there comes a point at which safety is not safe.

Posted on May 27, 2008 at 6:23 AM • View Comments

Terrorism as a Tax

Definitely a good way to look at it:

Fear, in other words, is a tax, and al-Qaeda and its ilk have done better at extracting it from Americans than the Internal Revenue Service. Think about the extra half-hour millions of airline passengers waste standing in security lines; the annual cost in lost work hours runs into the billions. Add to that the freight delays at borders, ports and airports, the cost of checking money transfers as well as goods in transit, the wages for beefed-up security forces around the world. And that doesn’t even attempt to put a price tag on the compression of civil liberties or the loss of human dignity from being groped in full public view by Transportation Security Administration personnel at the airport or from having to walk barefoot through the metal detector, holding up your beltless pants. This global transaction tax represents the most significant victory of Terror International to date.

The new fear tax falls most heavily on the United States. Last November, the Commerce Department reported a 17 percent decline in overseas travel to the United States between Sept. 11, 2001, and 2006. (There are no firm figures for 2007 yet, but there seems to have been an uptick.) That slump has cost the country $94 billion in lost tourist spending, nearly 200,000 jobs and $16 billion in forgone tax revenue—and all while the dollar has kept dropping.

Why? The journal Tourism Economics gives the predictable answer: “The perception that U.S. visa and entry policies do not welcome international visitors is the largest factor in the decline of overseas travelers.” Two-thirds of survey respondents worried about being detained for hours because of a misstatement to immigration officials. And here is the ultimate irony: “More respondents were worried about U.S. immigration officials (70 percent) than about crime or terrorism (54 percent) when considering a trip to the country.”

In Beyond Fear I wrote:

Security is a tax on the honest.

If it weren’t for attackers, our lives would be a whole lot easier. In a world where everyone was completely honorable and law-abiding all of the time, everything we bought and did would be cheaper. We wouldn’t have to pay for door locks, police departments, or militaries. There would be no security countermeasures, because people would never consider going where they were not allowed to go or doing what they were not allowed to do. Fraud would not be a problem, because no one would commit fraud. Nor would anyone commit burglary, murder, or terrorism. We wouldn’t have to modify our behavior based on security risks, because there would be none.

But that’s not the world we live in. Security permeates everything we do and supports our society in innumerable ways. It’s there when we wake up in the morning, when we eat our meals, when we’re at work, and when we’re with our families. It’s embedded in our wallets and the global financial network, in the doors of our homes and the border crossings of our countries, in our conversations and the publications we read. We constantly make security trade-offs, whether we’re conscious of them or not: large and small, personal and social. Many more security trade-offs are imposed on us from outside: by governments, by the marketplace, by technology, and by social norms. Security is a part of our world, just as it is part of the world of every other living thing. It has always been a part, and it always will be.

Posted on May 12, 2008 at 6:29 AM • View Comments

Overestimating Threats Against Children

This is a great essay by a mom who let her 9-year-old son ride the New York City subway alone:

No, I did not give him a cell phone. Didn’t want to lose it. And no, I didn’t trail him, like a mommy private eye. I trusted him to figure out that he should take the Lexington Avenue subway down, and the 34th Street crosstown bus home. If he couldn’t do that, I trusted him to ask a stranger. And then I even trusted that stranger not to think, “Gee, I was about to catch my train home, but now I think I’ll abduct this adorable child instead.”

Long story short: My son got home, ecstatic with independence.

Long story longer, and analyzed, to boot: Half the people I’ve told this episode to now want to turn me in for child abuse. As if keeping kids under lock and key and helmet and cell phone and nanny and surveillance is the right way to rear kids. It’s not. It’s debilitating—for us and for them.

It’s amazing how our fears blind us. The mother and son appeared on The Today Show, where they both continued to explain why it wasn’t an unreasonable thing to do:

And that was Skenazy’s point in her column: The era is long past when Times Square was a fetid sump and taking a walk in Central Park after dark was tantamount to committing suicide. Recent federal statistics show New York to be one of the safest cities in the nation—right up there with Provo, Utah, in fact.

“Times are back to 1963,” Skenzay said. “It’s safe. It’s a great time to be a kid in the city.”

The problem is that people read about children who are abducted and murdered and fear takes over, she said. And she doesn’t think fear should rule our lives.

Of course, The Today Show interviewer didn’t get it:

Dr. Ruth Peters, a parenting expert and TODAY Show contributor, agreed that children should be allowed independent experiences, but felt there are better—and safer—ways to have them than the one Skenazy chose.

“I’m not so much concerned that he’s going to be abducted, but there’s a lot of people who would rough him up,” she said. “There’s some bullies and things like that. He could have gotten the same experience in a safer manner.”

“It’s safe to go on the subway,” Skenazy replied. “It’s safe to be a kid. It’s safe to ride your bike on the streets. We’re like brainwashed because of all the stories we hear that it isn’t safe. But those are the exceptions. That’s why they make it to the news. This is like, ‘Boy boils egg.’ He did something that any 9-year-old could do.”

Here’s an audio interview with Skenazy.

I am reminded of this great graphic depicting childhood independence diminishing over four generations.

Posted on April 10, 2008 at 1:00 PM • View Comments

The Feeling and Reality of Security

Security is both a feeling and a reality, and they’re different. You can feel secure even though you’re not, and you can be secure even though you don’t feel it. There are two different concepts mapped onto the same word—the English language isn’t working very well for us here—and it can be hard to know which one we’re talking about when we use the word.

There is considerable value in separating out the two concepts: in explaining how the two are different, and understanding when we’re referring to one and when the other. There is value as well in recognizing when the two converge, understanding why they diverge, and knowing how they can be made to converge again.

Some fundamentals first. Viewed from the perspective of economics, security is a trade-off. There’s no such thing as absolute security, and any security you get has some cost: in money, in convenience, in capabilities, in insecurities somewhere else, whatever. Every time someone makes a decision about security—computer security, community security, national security—he makes a trade-off.

People make these trade-offs as individuals. We all get to decide, individually, if the expense and inconvenience of having a home burglar alarm is worth the security. We all get to decide if wearing a bulletproof vest is worth the cost and tacky appearance. We all get to decide if we’re getting our money’s worth from the billions of dollars we’re spending combating terrorism, and if invading Iraq was the best use of our counterterrorism resources. We might not have the power to implement our opinion, but we get to decide if we think it’s worth it.

Now we may or may not have the expertise to make those trade-offs intelligently, but we make them anyway. All of us. People have a natural intuition about security trade-offs, and we make them, large and small, dozens of times throughout the day. We can’t help it: It’s part of being alive.

Imagine a rabbit, sitting in a field eating grass. And he sees a fox. He’s going to make a security trade-off: Should he stay or should he flee? Over time, the rabbits that are good at making that trade-off will tend to reproduce, while the rabbits that are bad at it will tend to get eaten or starve.

So, as a successful species on the planet, you’d expect that human beings would be really good at making security trade-offs. Yet, at the same time, we can be hopelessly bad at it. We spend more money on terrorism than the data warrants. We fear flying and choose to drive instead. Why?

The short answer is that people make most trade-offs based on the feeling of security and not the reality.

I’ve written a lot about how people get security trade-offs wrong, and the cognitive biases that cause us to make mistakes. Humans have developed these biases because they make evolutionary sense. And most of the time, they work.

Most of the time—and this is important—our feeling of security matches the reality of security. Certainly, this is true of prehistory. Modern times are harder. Blame technology, blame the media, blame whatever. Our brains are much better optimized for the security trade-offs endemic to living in small family groups in the East African highlands in 100,000 B.C. than to those endemic to living in 2008 New York.

If we make security trade-offs based on the feeling of security rather than the reality, we choose security that makes us feel more secure over security that actually makes us more secure. And that’s what governments, companies, family members and everyone else provide. Of course, there are two ways to make people feel more secure. The first is to make people actually more secure and hope they notice. The second is to make people feel more secure without making them actually more secure, and hope they don’t notice.

The key here is whether we notice. The feeling and reality of security tend to converge when we take notice, and diverge when we don’t. People notice when 1) there are enough positive and negative examples to draw a conclusion, and 2) there isn’t too much emotion clouding the issue.

Both elements are important. If someone tries to convince us to spend money on a new type of home burglar alarm, we as society will know pretty quickly if he’s got a clever security device or if he’s a charlatan; we can monitor crime rates. But if that same person advocates a new national antiterrorism system, and there weren’t any terrorist attacks before it was implemented, and there weren’t any after it was implemented, how do we know if his system was effective?

People are more likely to realistically assess these incidents if they don’t contradict preconceived notions about how the world works. For example: It’s obvious that a wall keeps people out, so arguing against building a wall across America’s southern border to keep illegal immigrants out is harder to do.

The other thing that matters is agenda. There are lots of people, politicians, companies and so on who deliberately try to manipulate your feeling of security for their own gain. They try to cause fear. They invent threats. They take minor threats and make them major. And when they talk about rare risks with only a few incidents to base an assessment on—terrorism is the big example here—they are more likely to succeed.

Unfortunately, there’s no obvious antidote. Information is important. We can’t understand security unless we understand it. But that’s not enough: Few of us really understand cancer, yet we regularly make security decisions based on its risk. What we do is accept that there are experts who understand the risks of cancer, and trust them to make the security trade-offs for us.

There are some complex feedback loops going on here, between emotion and reason, between reality and our knowledge of it, between feeling and familiarity, and between the understanding of how we reason and feel about security and our analyses and feelings. We’re never going to stop making security trade-offs based on the feeling of security, and we’re never going to completely prevent those with specific agendas from trying to take care of us. But the more we know, the better trade-offs we’ll make.

This article originally appeared on Wired.com.

Posted on April 8, 2008 at 5:50 AM • View Comments

The Ineffectiveness of Security Cameras

Data from San Francisco:

Researchers examined data from the San Francisco Police Department detailing the 59,706 crimes committed within 1,000 feet of the camera locations between Jan. 1, 2005, and Jan. 28, 2008.

These were the total number of crimes for which police had reports—regardless of whether the crimes were caught on video. The idea was to look at whether criminals stopped committing crimes at those locations because they knew cameras were there.

Using a complicated method, researchers were able to come up with an average daily crime rate at each location broken out by type of crime and distance from the cameras. They then compared it with the average daily crime rate from the period before the cameras were installed.

They looked at seven types of crime: larcenies, burglaries, motor vehicle theft, assault, robbery, homicide and forcible sex offenses.

The only positive deterrent effect was the reduction of larcenies within 100 feet of the cameras. No other crimes were affected—except for homicides, which had an interesting pattern.

Murders went down within 250 feet of the cameras, but the reduction was completely offset by an increase 250 to 500 feet away, suggesting people moved down the block before killing each other.

The final report is expected to analyze the figures in more depth and to include other crimes, including prostitution and drug offenses.

This quote is instructive:

Mayor Gavin Newsom called the report “conclusively inconclusive” on Thursday but said he still wants to install more cameras around the city because they make residents feel safer.

That’s right: the cameras aren’t about security, they’re about security theater. More comments on the general issue here.

Posted on April 7, 2008 at 1:33 PM • View Comments

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Sidebar photo of Bruce Schneier by Joe MacInnis.