text: Appendix A
   Negligible. Little or no adverse impact on mission capability, first aid or minor medical
  treatment, slight equipment or systems damage (remaining fully functional or serviceable), or
  little or no property or environmental damage.
  * Threat vulnerability measures the ability of a threat to damage the target (asset) using available
  systems (people and material). Asset vulnerability is greater if a lower-level threat (Level I) can
  create damage or destruction that would result in mission failure or severely degrade its mission
  capability. If an asset can withstand a Level I or Level II threat, its vulnerability ability is less and
  may not require additional protection assets, depending on asset criticality. The following
  mitigating factors must be considered when assessing the vulnerability of a target: survivability
  (the ability of the critical asset to avoid or withstand hostile actions by using camouflage, cover
  [hardening], concealment, and deception), the ability to adequately defend against threats and
  hazards, mobility and dispersion, and recoverability (which measures the time required for the
  asset to be restored, considering the availability of resources, parts, expertise, manpower, and
  redundancies).
   Level I threat. Agents, saboteurs, sympathizers, terrorists, civil disturbances.
   Level II threat. Small tactical units. Irregular forces may include significant standoff
  weapons threats.
   Level III threat. Large tactical force operations, including airborne, heliborne, amphibious,
  infiltration, and major air operations.
  * Threat probability assesses the probability that an asset will be targeted for surveillance or attack
  by a credible/capable threat. Determinations of the intent and capability of the threat are key in
  assessing the probability of attack.
   Frequent. Occurs very often, known to happen regularly. Examples are surveillance, criminal
  activities, cyberspace attacks, indirect fire, and small-arms fire.
   Likely. Occurs several times, a common occurrence. Examples are explosive booby
  traps/improvised explosive devices, ambushes, and bombings.
   Occasional. Occurs sporadically, but is not uncommon. Examples are air-to-surface attacks
  or insider threats, which may result in injury or death.
   Seldom. Remotely possible, could occur at some time. Examples are the release of CBRN
  hazards or the employment of weapons of mass destruction.
   Unlikely. Presumably, the action will not occur, but it is not impossible. Examples are the
  detonation of containerized ammunition during transport or the use of a dirty bomb.
  A-32. The protection prioritization list helps Army commanders to identify or assess assets that require
  protection prioritization within their assigned areas. Not all assets listed on the protection prioritization list
  receive continuous protection. Some critical assets only receive protection assets based on available
  resources. It is the responsibility of the protection working group to provide the assessment and recommended
  protection prioritization list to the commander for approval (see table A-2).