The model is useful for developing safeguards for valuable documents or materials for either a fixed-site facility or a moving convoy against overt terrorist attack. In addition, the model can be used to rank sensitive areas at a security site to determine how and if they will survive a given hypothesized terrorist attack. Using event tree models, the site configuration, various defense strategies, and security configurations are computed. The computation utilizes a realistic engagement model and information on barrier penetration times. The methodology is illustrated by using two examples: a terrorist attack on a convoy carrying a missile from a storage to a launch facility and a terrorist attack on a munitions storage facility. The model is intended for the use of decision makers who must make security tradeoff analyses. 17 references. (Author abstract modified)