Britain Adopts Threat Levels

Taking a cue from a useless American idea, the UK has announced a system of threat levels:

"Threat levels are designed to give a broad indication of the likelihood of a terrorist attack," the intelligence.gov.uk website said in a posting. "They are based on the assessment of a range of factors including current intelligence, recent events and what is known about terrorist intentions and capabilities. This information may well be incomplete and decisions about the appropriate security response are made with this in mind."

Unlike the previous secret grading system offering seven levels of threat, the new system has been simplified to five, starting with "low," meaning an attack is unlikely, to "critical," meaning an attack is expected imminently. Unlike American threat assessments, the British system is not color-coded.

The current level is "severe":

"Severe" is the second-highest threat level, but the Web site did not say what kind of attack was likely. The assessment is roughly the same as it has been for a year.

I wrote about the stupidity of this sort of system back in 2004:

In theory, the warnings are supposed to cultivate an atmosphere of preparedness. If Americans are vigilant against the terrorist threat, then maybe the terrorists will be caught and their plots foiled. And repeated warnings brace Americans for the aftermath of another attack.

The problem is that the warnings don't do any of this. Because they are so vague and so frequent, and because they don't recommend any useful actions that people can take, terror threat warnings don't prevent terrorist attacks. They might force a terrorist to delay his plan temporarily, or change his target. But in general, professional security experts like me are not particularly impressed by systems that merely force the bad guys to make minor modifications in their tactics.

And the alerts don't result in a more vigilant America. It's one thing to issue a hurricane warning, and advise people to board up their windows and remain in the basement. Hurricanes are short-term events, and it's obvious when the danger is imminent and when it's over. People can do useful things in response to a hurricane warning; then there is a discrete period when their lives are markedly different, and they feel there was utility in the higher alert mode, even if nothing came of it.

It's quite another thing to tell people to be on alert, but not to alter their plans?as Americans were instructed last Christmas. A terrorist alert that instills a vague feeling of dread or panic, without giving people anything to do in response, is ineffective. Indeed, it inspires terror itself. Compare people's reactions to hurricane threats with their reactions to earthquake threats. According to scientists, California is expecting a huge earthquake sometime in the next two hundred years. Even though the magnitude of the disaster will be enormous, people just can't stay alert for two centuries. The news seems to have generated the same levels of short-term fear and long-term apathy in Californians that the terrorist warnings do. It's human nature; people simply can't be vigilant indefinitely.

[...]

This all implies that if the government is going to issue a threat warning at all, it should provide as many details as possible. But this is a catch-22: Unfortunately, there's an absolute limit to how much information the government can reveal. The classified nature of the intelligence that goes into these threat alerts precludes the government from giving the public all the information it would need to be meaningfully prepared.

[...]

A terror alert that instills a vague feeling of dread or panic echoes the very tactics of the terrorists. There are essentially two ways to terrorize people. The first is to do something spectacularly horrible, like flying airplanes into skyscrapers and killing thousands of people. The second is to keep people living in fear with the threat of doing something horrible. Decades ago, that was one of the IRA's major aims. Inadvertently, the DHS is achieving the same thing.

There's another downside to incessant threat warnings, one that happens when everyone realizes that they have been abused for political purposes. Call it the "Boy Who Cried Wolf" problem. After too many false alarms, the public will become inured to them. Already this has happened. Many Americans ignore terrorist threat warnings; many even ridicule them. The Bush administration lost considerable respect when it was revealed that August's New York/Washington warning was based on three-year-old information. And the more recent warning that terrorists might target cheap prescription drugs from Canada was assumed universally to be politics-as-usual.

Repeated warnings do more harm than good, by needlessly creating fear and confusion among those who still trust the government, and anesthetizing everyone else to any future alerts that might be important. And every false alarm makes the next terror alert less effective.

The Bush administration used this system largely as a political tool. Perhaps Tony Blair has the same idea.

Crossposted to the Schneier on Security blog