An engineering model for managing counter-terrorism

We believe society can use a modified engineering risk management model that frames terrorism as a combination of serial steps that can, if successful, lead to a terrorist event. Like the nuclear reactor fault tree, we suggest terrorist events be classified by the magnitude of the consequences based on a combination of property damage, deaths, and fear that each can create. We recommend an assignment of conditional probabilities to each of the steps necessary to complete a terrorist sequence (no matter how crude the estimate) and to calculate the probability of a terrorist event in terms of the serial conditional probabilities associated with each step. While the terrorist is attempting to maximize the combination of fear, property damage and deaths, the counter-terrorist wishes to minimize that combination. Minimization of a particular path can be accomplished by driving one of the conditional probabilities to near zero and thus, the counter-terrorist need not minimize every conditional probability. In contrast, the terrorist must maximize each conditional probability, i.e. he must practice total quality assurance-the most expensive solution for his success. This model can provide a method for assessing the value of a wide variety of counter-terrorist activities and provides guidance in the optimum allocation of resources to minimize the combination of fear, property damage and deaths of potential terrorist targets.