Definitions matter: a comparison of the global terrorism database and the U.S. governmental reports of terrorist incidents in Western Europe, 2002-2016.

Definitional assumptions within and across terrorism databases cause variations in terrorist incidents that can have impactful implications for time-series analyses. This study compares 2002–2016 Western Europe attacks recorded by the open source media Global Terrorism Database (GTD) and US governmental reports, Country Reports on Terrorism (formerly Patterns of Global Terrorism). The findings indicate significant differences exist between the GTD and US governmental reports related to location, type, perpetrators, and target of attacks. [ABSTRACT FROM AUTHOR]