The authors present and analyze a model of the frequency of severe terrorist attacks, which generalizes the recently proposed model of Johnson et al. This model, which is based on the notion of self-organized criticality and which describes how terrorist cells might aggregate and disintegrate over time, predicts that the distribution of attack severities should follow a power-law form with an exponent of α = 5/2. This prediction is in good agreement with current empirical estimates for terrorist attacks worldwide, which give α = 2.4 ± 0.2 and which the authors show is independent of certain details of the model. The authors close by discussing the utility of this model for understanding terrorism and the behavior of terrorist organizations and mention several productive ways it could be extended mathematically or tested empirically.
Araj, B.2008. Harsh state repression as a cause of suicide bombing: The case of the Palestinian-Israeli conflict. Studies in Conflict & Terrorism31 (4): 284-303.
2.
Asal, V., and R.K. Rethemeyer .2008. The nature of the beast: Organizational structures and the lethality of terrorist attacks. Journal of Politics70 (2): 437-49.
3.
Bak, P., C. Tang, and K. Wiesenfeld.1987. Self-organized criticality: An explanation of 1/f noise. Physical Review Letters59 (4): 381-84.
4.
Biggs, M.2005. Strikes as forest fires: Chicago and Paris in the late 19th century. American Journal of Sociology111 (1): 1684-1714.
5.
Cederman, L.-E.2003. Modeling the size of wars: From billiard balls to sandpiles . American Political Science Review97 (1): 135-50.
6.
Cioffi-Revilla, C., and P.P. Romero.2009. Modeling uncertainty in adversary behavior: Attacks in Diyala province, Iraq, 2002-2006. Studies in Conflict & Terrorism32 (3): 253-76.
7.
Clauset, A., and K.S. Gleditsch.2009. Developmental dynamics of terrorist organizations. Preprint. http://arxiv.org/abs/0906.3287 (accessed June 17, 2009).
8.
Clauset, A., L. Heger, M. Young, and K.S. Gleditsch. Forthcoming. The strategic calculus of terrorism: Substitution and competition in the Israel-Palestine conflict. Cooperation & Conflict.
9.
Clauset, A., C.R. Shalizi, and M.E.J. Newman.2009. Power-law distributions in empirical data. SIAM Review51(4): 661-703.
10.
Clauset, A., M. Young, and K.S. Gleditsch.2007. On the frequency of severe terrorist events. Journal of Conflict Resolution51 (1): 58-87.
11.
Cordes, B., B.M. Jenkins, K. Kellen, G. Bass, D. Relles, W. Sater, M. Juncosa, W. Fowler, and G. Petty.1985. A conceptual framework for analyzing terrorist groups. Arlington, VA: RAND.
12.
Cronin, A.K.2003. Behind the curve. International Security27 (3): 30-58.
13.
Crook, C.2006. The height of inequality. Atlantic Monthly298 (2): 36-37.
14.
Enders, W., and T. Sandler.2000. Is transnational terrorism becoming more threatening? A time-series investigation. Journal of Conflict Resolution44 (3): 307-32.
15.
Enders, W., and T. Sandler.2004. What do we know about the substitution effect in transnational terrorism? In Researching terrorism trends, achievements, failures, ed. A. Silke.London: Frank Cass.
16.
Fouda, Y., and N. Fielding.2003. Masterminds of terror: The truth behind the most devastating terrorist attack the world has ever seen. New York: Arcade.
17.
Harrison, M.2006. Bombers and by standers in suicide attacks in Israel. Studies in Conflict & Terrorism29:187-206.
18.
Johnson, N.F., M. Spagat, J. Restrepo, J. Bohorquez, N. Suarez, E. Restrepo, and R. Zarama.2005. From old wars to new wars and global terrorism. Preprint. http://arxiv.org/physics/0506213 (accessed June 29, 2005).
19.
Johnson, N.F., M. Spagat, J.A. Restrepo, O. Becerra, J.C. Bohorquez, N. Suarez, E.M. Restrepo, and R. Zarama.2006. Universal patterns underlying on going wars and terrorism. Preprint. http://arxiv.org/physics/0605035 (accessed May 3, 2006).
20.
Kleiber, C., and S. Kotz.2003. Statistical size distributions in economics and actuarial sciences. Hoboken, NJ: John Wiley.
21.
Kydd, A., and B. Walter.2002. Sabotaging the peace: The politics of extremist violence. International Organization56 (2): 263-96.
22.
Lacina, B.2006. Explaining the severity of civil wars. Journal of Conflict Resolution50 (2): 276-89.
23.
Li, Q.2005. Does democracy promote or reduce transnational terrorist incidents? Journal of Conflict Resolution49 (2): 278-97.
24.
Malamud, B.D., G. Morein, and D.L. Turcotte.1998. Forest fires: An example of self-organized critical behavior. Science281:1840-41.
25.
McKeown, L.2001. Out of time: Irish Republican prisoners Long Kesh 1972-2000 . Belfast, UK: Beyond the Pale.
26.
Mitzenmacher, M.2004. A brief history of generative models for power law and lognormal distributions. Internet Mathematics1 (2): 226-51.
27.
National Memorial Institute for the Prevention of Terrorism.2008. Terrorism knowledge base. http://www.tkb.org (accessed January 29, 2008).
Pape, R.A.2003. The strategic logic of suicide terrorism. American Political Science Review97 (3): 343-61.
30.
Pareto, V.1896. Cours d’ Economie Politique. Geneva, Switzerland: Droz.
31.
Pedahzur, A., and A. Perliger.2006. The changing nature of suicide attacks: A social network perspective. Social Forces84 (4): 1987-2008.
32.
Richardson, L.F.1948. Variation of the frequency of fatal quarrels with magnitude . Journal of the American Statistical Association43:523-46.
33.
Richardson, L.F.1960. Statistics of deadly quarrels. Pittsburgh, PA: Boxwood Press.
34.
Ruszczycki, B., B. Burnett, Z. Zhao, and N.F. Johnson.2008. Relating the microscopic rules in coalescence-fragmentation models to the emergent cluster-size distribution. Preprint. http://arxiv.org/abs/0808.0032 (accessed June 8, 2009).
35.
Sageman, M.2004. Understanding terror networks. Philadelphia : University of Pennsylvania Press.
36.
Simon, H.A.1955. On a class of skew distribution functions. Biometrika42 (34): 425-40.
37.
Small, M., and J.D. Singer.1982. Resort to arms: International and civil wars, 1816-1980. Beverly Hills, CA: Sage.
38.
U.S. Department of State.2004. Patterns of global terrorism, 2003. Washington, DC: U.S. Department of State. http://www.state.gov/documents/organization/31912.pdf (accessed January 22, 2005).
39.
Wilf, H.2006. Generating functionology. 3d ed. Wellesley, MA: A. K. Peters .
40.
Zipf, G.K.1949. Human behavior and the principle of least effort. Cambridge, MA: Addison-Wesley.
