Panel: DHS models for assessing terrorist threats poor
Standard risk models, such as those the DHS uses, assume that threat, vulnerability, and the consequences of risks are constants; an expert panel notes, though, that humans, unlike natural disasters, change their targets and tactics in response to protective measures that the authorities take against them, so the risk factors are no longer constant; the panel urges DHS to develop risk models that react dynamically to changing terrorist tactics; the report also says it may not be possible to quantify all risks: the risks posed by the fear and social disruption caused by terrorists are much harder to quantify than the risk of a bridge being blown up, for example
Only “low confidence” should be placed in most of the risk analyses of terrorist threats conducted by DHS, concludes a review by a National Research Council panel.
Created after the 9/11 attacks to cover national perils ranging from terrorism to natural disasters, DHS got off to a rough start. Critics blasted its lack of attention to natural disasters after its bungled response to hurricane Katrina.
Yet, Jeff Hecht writes, the panel finds that DHS models for natural disaster risks are “near the state of the art” and well suited to assess the effects of earthquakes, floods and hurricanes. It warns, however, that different techniques are needed to assess the risks posed by terrorism. “Natural hazard risks are quantifiable,” says panel chairman John Ahearne of Duke University. “Many terrorism risks are not quantifiable because of uncertainties arising from having an intelligent adversary.”
Standard risk models, such as those the DHS uses, assume that threat, vulnerability, and the consequences of risks are constants. The panel notes, though, that humans, unlike natural disasters, change their targets and tactics in response to protective measures that the authorities take against them, so the risk factors are no longer constant. The report urges DHS to develop risk models that react dynamically to account for this.
It also says the DHS “appears to be at a very immature state with respect to characterizing uncertainty” in its risk assessments, an issue that is key to making sound decisions based on the risks.
Moreover, the report says it may not be possible to quantify all risks. The risks posed by the fear and social disruption caused by terrorists are much harder to quantify than the risk of a bridge being blown up, for example. “Qualitative comparisons can help illuminate the discussion of risks and thus aid decision makers,” it says.
