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Although individual models and simulations can help predict specific behaviors (contamination plume transport and diffusion, transportation network performance, etc.), overall preparedness and response actions depend upon the integrated effects. There are several centers focused on modeling and simulation throughout the nation. Each of these has tended to be singularly focused on a particular weapon of mass destruction (WMD), or exploring a particular effect. More intensive modeling of multiple simultaneous events or effects remains relatively unexplored. For example, while a biothreat (BT) agent or nuclear detonation effects have been simulated, simultaneous population behavior, reverberations from economic effects and degradation of response capability over time have not been attempted.

The Brookings Center on Social and Economic Dynamics (CSED) is a world leader in modeling and simulation of large-scale human social and behavioral dynamics. CSED pioneered the methodology of agent-based computational modeling; a research tool that is particularly well suited to exploring how the interaction of individuals can shape mass behavior, such as responses to political, economic, environmental or other social shocks. The approach has been powerfully applied to a wide range of social phenomena from civil violence to behavior in epidemics. It is particularly strong in capturing the individual behavioral and psychological factors that shape mass responses to political, economic, environmental or other social shocks, terrorist attacks included. Because it is rule-based (rather than equation-based) and is highly visual, it is extremely valuable as an environment for crisis simulation and training in government, and for education more broadly. Finally, the modeling has a strong empirical base in a PACER-led effort to develop new, cross-country data sets which capture the interaction between economic and psychological factors in determining human well being and decision-making. The modeling capability and data collection efforts are novel and centrally aligned with the emphasis on containment both of pathogens and of public panic that could spread through networks of partially informed citizens, leading to flight, crowding, and exacerbation of crises.

Economic policy modeling typically assumes homogeneous agents; indeed, in macroeconomics, a single “representative agent” is posited. Like homo economicus, people in these models are assumed behave optimally, using perfect (global) information. Effects of space and of social networks are typically ignored. Finally, static equilibria are computed; shocks, “tipping phenomena,” and dynamics are seldom considered. These classic assumptions are likely to be profoundly misleading in projecting the economic effects of terrorist events. Particularly, in terror crises, information will be poor, people will not behave rationally, epidemics of panic will spread through networks, and spatial patterns will abruptly change (e.g., flight patterns after 9/11). These effects will be cumulative and ramify in highly nonlinear ways not captured by standard economic modeling techniques. The agent-based computation approach is expressly designed to handle situations of this sort. Space is explicit in these models (where it is largely absent from standard approaches) and our focus is expressly on dynamics, not the usual static equilibria. Our conviction is that this approach is far more likely to produce useful policy guidance and economic resilience than traditional methods.