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How a System Backfires: Dynamics of Redundancy Problems in Security


*Address correspondence to Navid Ghaffarzadegan, Milne Hall 300, Rockefeller College, 135 Western Avenue, University at Albany State University of New York, Albany, NY 12222, USA; tel: 518-364-5731; fax: 518-442-3398;


Increasing attention is being paid to reliability, safety, and security issues in social systems. Scott Sagan examined why more security forces (a redundancy solution) may lead to less security.(1) He discussed how such a solution can backfire due to three major issues (i.e., “common-mode error,”“social shirking,” and “overcompensation”). In this article, using Sagan's hypotheses, we simulate and analyze a simple and generic security system as more guards are added to the system. Simulation results support two of Sagan's hypotheses. More specifically, the results show that “common-mode error” causes the system to backfire, and “social shirking” leads to an inefficient system while exacerbating the common-mode error's effect. Simulation results show that “overcompensation” has no effect of backfiring, but it leads the system to a critical state in which it can easily be affected by the common-mode error. Furthermore, the simulation results make us question the importance of the initial power of adversaries (e.g., terrorists) as the results show that, for any exogenous level of adversary power, the system endogenously overcompensates to a level that makes the system more susceptible to being attacked.