October 16, 2003

Letter to the Editor

To the Editor,

I am flattered by Rafi Youatt's extensive commentary in the Maroon's last issue on my recent article on suicide terrorism in the American Political Science Review. This is testimony to the intellectual vibrancy that we consider so valuable at the University of Chicago. However, the piece is not accurate in three respects.

First, my article did not sample suicide terrorism. My research collected the universe of suicide terrorist attacks worldwide from 1980-2001. It is the only database of its kind so far. Officials who track terrorism for our government tell me that they have no comparable data, nor do Israel or Great Britain (the other two countries that have invested great efforts in this).

Second, my article does not claim that occupation always causes suicide terrorism. It claims that suicide terrorism is more likely associated with occupation than non-occupation. This finding is based on the fact that there have been 16 important suicide terrorism campaigns since 1980. All 16 are associated with military occupations, none with non-occupation. Compared to chance (i.e. a coin flip between occupation and non-occupation), this result would occur less than 1 in 55,000 trials, far less than the .05 level of significance that is the standard benchmark in statistical studies.

Had I gone further to claim that occupation always causes suicide terrorism—or that occupation is the only important causal factor—then I would have been claiming more than the data support. I make no such claims. Occupation appears a necessary condition, but we have as yet little understanding of what might constitute sufficient conditions. Many have asked if we could deepen the research to explore a wider set of occupations in order to explain why some occupations lead to suicide terrorism but others do not. I am now conducting such a study.

Robert A. Pape

Associate Professor

Political Science Department

University of Chicago