The Threat from Within: A Conjunctive Analysis of Domestic Terrorism Incidents in the United States, United Kingdom, and Ireland

This study examines outcomes of domestic terrorism incidents to determine if similarities exist within or between the United States, United Kingdom, and Ireland based on four perpetrator types: right-wing, left- wing, nationalist/ separatist, and single issue. We used data from the Global Terrorism Database to examine key characteristics of domestic terrorism incidents including perpetrator, target, attack, and weapon types and their relationship to incident outcomes. We identified dominant configurations of these key incident characteristics using conjunctive analysis of case configurations and used those configurations to determine if similarities existed between dominant configurations for each perpetrator type both within and between countries. Our analysis identifies the characteristics most prevalent in configurations resulting in property damage, injuries or fatalities, and successful attacks. Although differences exist in each country’s experiences with domestic terrorism, the results of our analysis reveal several similarities between the incidents attributed to the perpetrator types in each country, including the targets, attack types, and weapons used. The results of this study suggest future comparative research is required to identify the causes and consequences of these similarities in each country.