Democratic terroritorial occupation, and suicide terrorism

Scott Ashworthy, Joshua D. Clinton, Adam Meirowitz, and Kristopher W. Ramsay:

[I]f a terrorist group chooses suicide tactics, then it is highly probable that a democratic country is occupying its homeland. This fact is certainly consistent with the existence of a "close association between foreign military occupations and the growth of suicide terrorist movements." In the remainder of this paper, however, we show that it is also consistent with either a weak or non-association, as well as with a strong negative association. The data Pape collects are only minimally informative about the association between military occupation and suicide attacks.
...
It is important to note that our critique of Pape's analysis does not make the well-known point that association does not imply causation. Rather, because Pape collects only instances of suicide terrorism, his data do not even let him calculate the needed associations. The conditional probability of suicide terror tactics given territorial occupation, religious extremism, or any other potential cause, is unidentied and, thus, the attributable risk is also unidentied. Only after these identication issues are resolved can the equally important issue of determining whether the correlations have a causal interpretation be addressed.

The paper (pdf) is here. Thanks to The Monkey Cage for the pointer.