For the purposes of this question, a CCTA is an [1] act of terrorism [2] involving multiple perpetrators working in concert [3] initiated with little or no warning [4] and employing one or more weapon systems (e.g., firearms, explosives, fire as a weapon, poison gas) [5] that is intended to result in large numbers of casualties. For the purposes of this question, "terrorism" is as defined by EU law (European Council, see "EU definition of terrorism"). Examples of CCTAs include the 2004 Madrid train bombings, the 2008 Mumbai attacks, 2013 Boston Marathon bombings, and the 2015 San Bernardino, CA, office attack. Fatalities must occur during the question's duration to count. "Continental Europe" includes the territory on the continent of any country that is part of the European single market, as well as Andorra, Monaco, San Marino, and Vatican City (Gov.uk - Countries in the EU and EEA, does not include UK). The hijacking or bombing of an aircraft would count if the aircraft last took flight from continental Europe or fatalities occur within the territory or airspace of a continental European country, and an attack in the territorial waters of a continental European country would count.

Confused? Check our FAQ or ask us for help. To learn more about Good Judgment and Superforecasting, click here.

To learn more about how you can become a Superforecaster, see here. For other posts from our Insights blog, click here.