Is ALARP applicable to the management of terrorist risks?

In this paper, we discuss the applicability of the as low as reasonable practicable (ALARP) principle to terrorist risk management. ALARP is a commonly used framework for managing risk due to non-intelligent threats, but terrorism introduces difficult issues, both technically and socially. In particular, the probability of a terrorist attack is difficult to define, terrorist threats are adaptive, and some terrorist risk management actions raise issues of loss of civil liberties not raised by risk management measures for other types of risk. We discuss these issues and their implications for risk management. After showing how ALARP is used to manage the risk from other hazards in different economic sectors, we discuss both the benefits and difficulties associated with extending the ALARP framework for terrorist risk analysis. We conclude that the ALARP framework can be modified to make it appropriate for risk management for adaptive risks, provided that care is taken to explicitly consider adaptive reallocation of risk in response to risk management actions, to account for perceived or actual loss of civil liberties resulting from risk management actions, and to consider the difficulties associated with using probability to measure uncertainty in adversary actions.