This is the fourth edition of the Global Terrorism Index which provides a comprehensive summary of the key global trends and patterns in terrorism over the last 16 years, covering the period from the beginning of 2000 to the end of 2015. Produced by the Institute for Economics and Peace, the GTI is based on data from the Global Terrorism Database which is collected and collated by the National Consortium for the Study of Terrorism and Responses to Terrorism (START), a Department of Homeland Security Centre of Excellence led by the University of Maryland. The Global Terrorism Database is considered to be the most comprehensive dataset on terrorist activity globally and has now codified over 150,000 terrorist incidents.