Terrorism has two characteristics that make it prone to myth making--its black swan nature and its burstiness. Essayist Nassim Taleb defines a black swan incident as one that falls outside the realm of regular expectations, has a high impact, and defies predictions. The term is based on the observation that before they visited Australia, Europeans had assumed that all swans were white; an assumption that at the time was supported (for Europeans at least) by their own experience. Taleb claims that the coordinated terrorist attacks of 9/11 are a perfect example of a black swan event because they were unexpected, had a huge impact on policy and were difficult to predict. One of the major challenges in responding to terrorism is that a handful of very rare cases can have a disproportionate effect on setting the agenda for the phenomena more generally.
LaFree, Gary. 2012. "Black Swans and Burstiness -- Countering Myths about Terrorism." START (December): www.start.umd.edu/news/discussion-point-black-swans-and-burstiness-countering-myths-about-terrorism