The chance of dying in a terrorist attack perpetrated by a refugee is 1 in 3.64 Billion

For comparison, the nominal murder rate in the U.S. is 3.9 per 100,000

CATO Findings

  • The study covers a history of immigrant terrorism concerns, including Irish, Vietnamese, and Cuban immigration
  • The study covers 3,432 murders classified as terrorism in the 41-year period between 1975 and 2015
  • The chance of an American perishing in a terrorist attack perpetrated by a non-citizen is 1 in 3.6 Million.  For comparison, the odds of dying in a car accident are 1/9,000.
  • The chance of dying in a terrorist attack perpetrated by a refugee is 1 in 3.64 Billion
  • The chance of dying in a terrorist attack perpetrated by an illegal immigrant is 1 in 10.9 Billion
  • A tourist visa had the highest murder rate, accounting for 2,834 of 3,024 deaths.  Still, that’s only 1 in 3.85 Million; the nominal murder rate is 150 times this.
  • The 2nd highest statistic was for a student visa
  • Refugees accounted for 3 of the 3,024 deaths classified under foreign-born terrorism
  • Since 9/11, there have only been 5 successful foreign-born terrorists, accounting for 24 deaths total.
  • There were only three terrorists on the Visa Waiver Program during the life of the program (since 1986), which amounts to a single terrorist for every 129 million entries
  • An immigration moratorium would have to prevent 504 times the number of murders in any given year as actually occurred annually from 1975 through 2015 for the costs of the moratorium to equal the benefits.
Murder by foreign-born terrorists is nearly a non-statistic compared to the nominal US murder rate


Foreign-born terrorism on U.S. soil is a low probability event that imposes high costs on its victims despite relatively small risks and low costs on Americans as a whole. From 1975 through 2015, the average chance of dying in an attack by a foreign-born terrorist on U.S. soil was 1 in 3,609,709 a year. For 30 of those 41 years, no Americans were killed on U.S. soil in terrorist attacks caused by foreigners or immigrants. Foreign-born terrorism is a hazard to American life, liberty, and private property, but it is manageable given the huge economic benefits of immigration and the small costs of terrorism. The United States government should continue to devote resources to screening immigrants and foreigners for terrorism or other threats, but large policy changes like an immigration or tourist moratorium would impose far greater costs than benefits.

The Full Report

CATO Policy Analysis on Immigration and Terrorism