Document Type


Publication Date




Publication Title

Journal of Homeland Security and Emergency Management






8 (7 pages)


Currently, the U.S. Department of Homeland Security (DHS) elicits probabilistic judgements from the intelligence community on actions terrorists may take to attack the continental U.S. For example, how likely is the adversary to choose agent 'x' over 'y' or target 'a' over target 'b'? Eliciting these types of judgements is difficult and time consuming. The National Academies and others have suggested that a better approach may be to elicit information on adversary's preferences, perceptions, and capabilities and use this information to calculate probabilities of interest to DHS. Some terrorist groups are thinking about using weapons of mass destruction (WMD), each with its own values, perceptions of reality, and capabilities. This presentation details the findings on the factors & relationships among factors that lead to a terrorist decision to initiate an attack against the continental U.S. as well as target selection. To accomplish this, we assembled international experts in WMD, adversary modeling, political science, terrorism, psychiatry, social sciences as well as experts from national laboratories, the Commonwealth of Virginia State Fusion Center, and Hampton Roads Emergency Management.

This paper provides a summary of the findings from an Adaptive Adversary Workshop. In this paper, we provide an overview of the motivation for and design of the workshop as well as 19 emerging themes. The purpose of the workshop was to illicit expert opinions on terrorist decision-making and target selections in an effort to improve our understanding of adversaries (individuals, local/regional groups, transnational groups, states) who may initiate a bioterrorism attack in the from of releasing biological agents upon U.S. interests. Furthermore, these expert opinions are intended to be used to inform Bayesian Belief Network (BBN) models of terrorist networks. These models must be informed or populated with substantive information about the intelligent and adaptive adversary who may initiate an attack. To this end, a conceptual framework, informed broadly by the social sciences community, is intended to capture the terrorists' motivations, methods, and decision calculi.


Article funded in part by the Battelle National Biodefense Institue Contract # 792981.

Original Publication Citation

Ezell, B. C., Behr, J., & Collins, A. (2012). Identifying factors that influence terrorist decisions and target selection. Journal of Homeland Security and Emergency Management, 9(1), 8. doi:10.1515/1547-7355.1974


0000-0003-4274-908X (Ezell)