GAO obtained information on how the Homeland Security Advisory System operates, including the process used to notify Federal, State, and local government agencies, private industry, and the public of changes in the threat level. GAO also reviewed literature on risk communication to identify principles and factors to be considered when determining when, what, and how information should be disseminated about threat-level changes. GAO also researched the type of information that had been provided to the aforementioned entities regarding terrorist threats. Attention was given as well to the suggestions given to these entities by the Homeland Security Advisory System for implementing code-orange alerts. GAO found that the entities typically received general information from the Homeland Security Advisory System on why the national threat level was changed, but they did not receive specific information on such matters as threat locations or time frames; however, for the December 21, 2003, to January 9, 2004, code-orange alert period, information was received that the aviation industry and certain geographic locations were at particularly high risk. The entities have been provided with suggested protective actions for responding to increases in the threat level from code yellow to code orange. Federal, State, and local government officials have indicated they need more specific threat information. Federal agencies want more information on likely locations and types of terrorist threats. One State official indicated that receiving more specific information about likely threat targets would enable the State to focus its response on high-risk threats. In most cases, the State has no recourse but to blanket the State with increased general security measures. One local official recommended that specific information about the location of a threat should be provided to law enforcement agencies throughout the Nation, not just to localities believed to be threatened; this would allow other local governments to determine whether they might be indirectly affected and respond accordingly. 33 notes