Islamist Terrorism, Diaspora Links and Casualty Rates

We explore the widespread belief that Islamist groups are especially violent and also consider the possibility that links with transnational diasporas may reduce casualties by Islamist terrorist organizations. Analyzing between 77,000 and 82,000 terrorist incidents from 1970 to 2016, we find that attacks by Islamist groups produce fewer casualties than attacks by non-Islamist religious groups. We also find that Islamist groups with links to diaspora kin abroad commit lower casualty terrorist attacks. We explain these findings by arguing that Islamic diaspora communities impose tactical restraints on terrorist organizations with which they are linked. Diasporas constitute a major political audience and source of support for terrorist organizations and provide an audience outside the homeland that may be negatively affected by extremely violent attacks.