Since 9/11, terrorism has loomed large as a pervasive security issue. Has terrorism really reached an unprecedented level, or has sensational news coverage inflated the threat? Is terrorism a danger in some places more than others?
To start answering those questions, the first step is to determine what actually counts as a terrorist attack.
Defining terrorism is a challenge, requiring researchers to make a number of decisions when classifying incidents as terrorist attacks.
The Global Terrorism Database, operated by START at the University of Maryland, is the largest public database on terrorist violence. It is a compilation of every terrorism incident on record since 1970 and includes information detailing the location of each attack, the group responsible, the type of weapon used, the number of casualties, and more.
START’s definition of a terrorist incident is based on three criteria; an attack must meet at least two of those to be listed in the START database:
- The violent incident is designed to meet a political, economic, religious, or social goal.
- It’s meant to coerce, intimidate, or convey another message to a broader audience.
- It targets civilians and is not an act of war.
Terrorism is, by definition, frightening. When fear drives decision-making, the resulting policies can easily respond to the wrong threats. Collecting global data on terrorist attacks and deaths allows researchers to confirm or challenge claims about the threat of terrorism, which can be inflated by politicians or media coverage. The data collected by START reveals, among other things, that the vast majority of terrorist attacks don’t make international headlines, and half of terrorist attacks claim no lives. A comprehensive look at terrorism allows policymakers to develop strategies that take into account the real nature of terrorist attacks: the groups responsible, the methods they use, the grievances that drive them, and the places they act.
What trends emerge from the data?
Zeroing in on the United States reveals that terrorism-related deaths have increased since 2012 after a decade of remaining relatively low. The spike in 2012 was driven by a slight increase in terrorist attacks but mostly, in fact, by a few particularly lethal mass shootings. Because the overall volume of terrorist attacks in the United States is low relative to other parts of the world, one attack with a significant number of casualties can have an outsize effect on the data. The 2017 shooting in Las Vegas, for example, killed fifty-eight people, causing the trend line to shoot up. And while the upward trend is worrying, data on terrorism-related deaths and attacks occurring in the United States, versus in other parts of the world, makes clear that Americans face a relatively low threat from terrorism.