Security Journal

, Volume 25, Issue 3, pp 244–264 | Cite as

Self-exciting point process models of civilian deaths in Iraq

  • Erik Lewis
  • George Mohler
  • P Jeffrey Brantingham
  • Andrea L Bertozzi
Original Article

Abstract

Our goal in this article is to characterize temporal patterns of violent civilian deaths in Iraq. These patterns are expected to evolve on time-scales ranging from years to minutes as a result of changes in the security environment on equally varied time-scales. To assess the importance of multiple time-scales in evolving security threats, we develop a self-exciting point process model similar to that used in earthquake analysis. Here the rate of violent events is partitioned into a background rate and a foreground self-exciting component. Background rates are assumed to change on relatively long time-scales. Foreground self-excitation, in which events trigger an increase in the rate of violence, is assumed to be short-lived. We explore the model using data from Iraq Body Count on civilian deaths between 2003 and 2007. Our results indicate that self-excitation makes up as much as 37–50 per cent of all violent events and that self-excitation lasts at most between two and six weeks, depending upon the district in question. Appropriate security responses may benefit from taking these different time-scales of violence into consideration.

Keywords

modeling violence point process rational choice theory routine activity theory density estimation 

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Copyright information

© Palgrave Macmillan, a division of Macmillan Publishers Ltd 2011

Authors and Affiliations

  • Erik Lewis
    • 1
  • George Mohler
    • 2
  • P Jeffrey Brantingham
    • 3
  • Andrea L Bertozzi
    • 1
  1. 1.Department of MathematicsUniversity of California – Los AngelesUSA
  2. 2.Department of Mathematics and Computer ScienceSanta Clara UniversitySanta ClaraUSA
  3. 3.Department of AnthropologyUniversity of CaliforniaLos AngelesUSA

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