choice.67 Many individuals are not willing to invest in security for a number of reasons that include myopia, high discount rates, and budget constraints. Others take action because of anxiety and worry. These issues need to be considered when developing more realistic models of choice.

The possibility of an attack on any unit in the system is likely to be influenced by what protective measures it has taken. Hence, these probabilities should be treated as endogenous. In the case of the chemical supply chain, terrorists are more likely to focus on targets that are less protected.68 Future research should examine how changes in endogenous probabilities impact IDS solutions and the appropriate strategies for improving the performance of individual units as well as the operation of the entire chemical supply chain.

Economic studies to explore the interdependencies of the supply chain, determine how these impact decision making on security measures, and determine the least secure links in the chain is appropriate. DHS’s National Assets Database and its ongoing Risk Analysis for Critical Assets Protection (RAMCAP) analysis should be useful in identifying units that represent weak links in the security of the chemical supply chain.69


Kahneman, D., and A. Tversky. 2000. Choices, Values and Frames. New York, NY: Cambridge University Press.


Kunreuther, H., and H. Geoffrey. 2003. Interdependent security. Journal of Risk and Uncertainty, Special Issue on Terrorist Risks 26:231-249.


The committee did not have access to the National Assets Database or to the results of the RAMCAP exercise.

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