The working group must establish criteria for evaluating the severity of the potential consequence of an agent being successfully used to commit a terrorist act. The exact evaluation criteria will depend on the specific facilities and operations being considered. The following criteria were used in a recent threat assessment; they provide an illustration of the considerations that typically apply in evaluating the severity of an incident.

Impact to Health and Safety

The Impact to Health and Safety criterion was subdivided into four elements:

• Exposure
• Individual Impact 
• Diagnosis
• Treatment

For the Exposure element, high ratings were awarded to threat agents for which the effects would occur throughout or beyond a facility, whereas low ratings were awarded to threat agents for which the effects would be limited to the immediate area of the release or require physical contact with the agent source. For all threat agent scenarios, four checklist items were considered as potentially applicable. In assigning overall ratings, working group members exercise professional judgment in how the various checklist items are weighted based on knowledge of which items were most significant for the agent being evaluated.

Checklist Item	Descriptors
Probability that initially exposure affects/infects individuals	High = most, Medium = limited subsets, Low = very small percentage affected
Probability that exposure can be passed to others	High = Readily transmitted or contagious, Medium = Transmitted under limited circumstances, Low = Not likely to be passed to others
Agent persistence/hardiness/mobility	High = both persistent/hardy and mobile, Medium = either persistent or mobile, Low = Nonpersistent and immobile
Initial awareness of incident/exposure	High = no initial awareness, Medium = immediate awareness of effects, but not of cause, Low = immediate awareness of effects and their cause

For the Individual Impact element, high ratings were awarded to threat agents that pose a high likelihood of fatality or permanent disability at achievable concentrations of agent, whereas low ratings were awarded to threat agents for which the effects are short-termed and limited. For all threat agent scenarios, three checklist items were considered as potentially applicable.

Checklist Item	Descriptors
Lethality of agent	High = fatality at achievable concentrations of agent, Medium = severe or prolonged illness or injury, Low = short-term mild illness, injury, or discomfort
Disabilities caused by exposure	High = permanent disability, Low = No permanent effects
Chronic health effects	Medium = Substantial increased risk of chronic effects, Low = Nominal increased risk of chronic health effects

For the Diagnosis element, high ratings were awarded to threat agents for which the diagnosis of the incident’s effects would be relatively difficult, whereas low ratings were awarded to threat agents for which the diagnosis of the incident’s effects would be relatively simple. For all threat agent scenarios, five checklist items were considered as potentially applicable.

Checklist Item	Descriptors
Confounding factors	High = easily confused with less serious conditions, Medium = symptoms not common to other less serious conditions, Low = No confounding factors
Level of specialization required to make diagnosis	High = CDC or national-level expert required, Medium = Specialist required, Low = Initial health care provider, e.g., primary care physician or EMT responder
Time required for diagnosis	High = days, e.g., test results from a national expert lab, Medium = up to a day, e.g., test results from a local clinical lab, Low = hour or so, e.g., in-office testing
Availability of required tests	High = not sufficiently available, Medium = specialized equipment required, Low = available in primary care physician's office
Time required for symptoms to appear	High = days, Medium = hours, Low = minutes or less

For the Treatment element, high ratings were awarded to threat agents for which no effective treatment is possible, whereas low ratings were awarded to threat agents for which treatments are simple, economical, and widely available. For all threat agent scenarios, four checklist items were considered as potentially applicable.

Checklist Item	Descriptors
Availability of treatment	High = None exists, Medium = requires specialists or exotic drugs, Low = Widely available, e.g., any local hospital or off the shelf at most pharmacies
Time required for intervention	High = Treatment may not be available before deaths begin to occur, Medium or Low = Treatment should be available in time for successful outcome
Complexity of treatment	Medium = Complex and expensive, e.g., many referrals anticipated, Low = simple and economical, e.g., a few visits to a primary care physician
Length of treatment	Medium = Months or more, Low = one week or less

Impact to Customer

The criteria developed and the checklist items used to evaluate the criteria will depend on the nature of a customer's operation. For one example assessment, the criterion for the impact to Noblis' customer was subdivided into two elements:

• Physical Effects
• Secondary Impacts

For the Physical Effects element, high ratings were awarded to threat agents that would impact an extended set of facilities, whereas low ratings were awarded to threat agents that would have limited impact only. Checklist items included recovery costs, operational capability, impact on physical assets, and recovery period to return to normal service.

For the Secondary Impacts element, high ratings were awarded to threat agents for which the secondary impacts were more costly, whereas low ratings were awarded to threat agents for which the secondary impacts were less costly. Checklist items included worker's compensation costs, impact on customer confidence and brand, and lost revenue.

Building Decontamination is a major impact to any organization that is targeted with a WMD device. Noblis experts on the expert panel can evaluate the feasibility of decontamination, and can estimate the length of time and type of decontamination required to return a facility to operation following a WMD attack.

Impact to U.S. and Commerce 

For the Impact to U.S. and Commerce criterion, high ratings were awarded to threat agents that were judged likely to cause long delays, make the public feel vulnerable, and have high financial impacts. Low ratings were awarded to threat agents that were judged likely to cause minimal delays and have lower financial impacts, and less likely to make the public feel vulnerable. Checklist items included articles delayed or lost, homeland security, and financial impact on employees, the public as individuals, and major customers.