Insurgency and Small Wars: Estimation of Unobserved Coalition Structures Francesco Trebbi Eric Weese October 2017 Discussion Paper No.1628 GRADUATE SCHOOL OF ECONOMICS KOBE UNIVERSITY ROKKO, KOBE, JAPAN Insurgency and Small Wars: Estimation of Unobserved Coalition Structures Francesco Trebbi and Eric Weese∗ October 2017 Abstract Insurgency and guerrilla warfare impose enormous socio-economic costs and often persist for decades. The opacity of such forms of conflict is an obstacle to effective international humanitarian intervention and development programs. To shed light on the internal organization of otherwise unknown insurgent groups, this paper proposes two methodologies for the detection of unobserved coalitions of militant factions in conflict areas. Our approach is based on daily geocoded incident-level data on insurgent attacks. We provide applications to the Afghan conflict during the 2004-2009 period and to Pakistan during the 2008-2011 period, identifying systematically different coalition structures. Further applications to global terrorism data are discussed. ∗University of British Columbia, Vancouver School of Economics, CIFAR and NBER,
[email protected]; Kobe University,
[email protected] respectively. The authors would like to thank Eli Berman, Ethan Bueno de Mesquita, James Fearon, Patrick Francois, Camilo Garcia- Jimeno, Jason Lyall, Carlos Sanchez-Martinez, Jake Shapiro, Drew Shaver, Austin Wright and seminar participants at UCSD, Penn, Chicago Harris, Columbia, Stanford, Berkeley, Rochester, UQAM, Kobe, Tokyo, Toronto, CIFAR, and Princeton for useful comments and discussion and the researchers at the Princeton University Empirical Studies of Conflict Project for generously sharing their incident data online. Nathan Canen provided excellent research assistance. We are grateful to the Social Science and Humanities Research Council for financial support.