The color-coded Homeland Security Advisory System (HSAS) might be an innovative attempt to warn the public of potential terrorist attacks, but APA psychologists say the system faces many challenges.

APA's formal comments suggest the five-color HSAS code, which indicates the level of a terrorist threat , raises several concerns. They include:

  • The public interprets terms such as "low," "high" or "severe" differently, making it challenging for government officials to categorize situations in a consistent way.

  • Colors carry natural connotations. For instance, green signifies lowest risk while blue is more extreme, yet this conflicts with the order of the color spectrum.

  • The distinction between "probability of an event" and "severity of consequences" might confuse people. This could be helped if sample situations were cited for each level, such as Level 2 (guarded)--"someone threatening to release tear gas in a shopping mall."

APA also cautions that if the public is constantly being warned of a potential attack, "alertness fatigue" could set in. As a result, for example, Level 5 should only be used when the probability of attack is 100 percent or already in progress, says Baruch Fischhoff, PhD, who helped draft APA's comments.

"One thing that I think is frustrating or confusing for people is that many people are not sure whether there is a consistent standard being used for issuing these alerts," says Fischhoff, professor of social and decision sciences at Carnegie Mellon University. Furthermore, some question whether the alerts are politically motivated, he noted.

"An alert system that communicates consistently, credibly and focuses on the public's best interests would be really useful to people," Fischhoff says. "If [the government] can do that, then we will learn to override our traditional color norms."