Lies, Damn Lies, and Statistics: Refugees and Terrorism

When President Trump issued his executive order on immigration, it reignited the issue of Syrian refugees, and the popular statistic “you only have a one in 3.64 billion chance of being killed by a refugee”[1] began circulating widely on social media.

This statistic, while factually correct, is severely misleading when used out of context. Advocating using it as a driving force behind public policy grossly misunderstands both probability and how probability is used in security policy.

It is important to look at this in its wider context: “you have a one in 3.64 billion chance of being killed by a refugee.” There is a significantly higher chance that any given refugee is a terrorist (one in 162,625). These are reached by calculating together that out of 3,252,493 refugees admitted to the US, 20 were terrorists. Between those 20, they succeeded in killing three Americans. The total deaths were divided by America’s population since 1975 to reach one in 3.64 billion[2].

It is misleading to rely on historical data alone for determining the probability of a future event. FEMA training and guidance warns directly against this practice.

“Communities should take care to not over-rely on historical averages or patterns that may give a false sense of likelihood,”[3] the Department of Homeland Security warns.

Historical data is remarkably bad at predicting the future, especially aberrations like terrorist attacks. Prior to 9/11, the “likelihood” that 19 foreigners would be able to destroy the World Trade Center and directly attack the Pentagon would have been effectively zero. It happened nonetheless.

Estimating probability (or likelihood) is also only one part of the process for determining risk and creating policy. Other values are weighed, including consequence and vulnerability. If something is highly unlikely but would have a catastrophic consequence, then it’s assigned a high-risk value despite being very unlikely.

The part of the discussion that always gets glossed over is that there is a risk inherent in the refugee system (or letting any foreign nationals into the country for that matter), and there always will be. We know that terrorist organizations are attempting to embed their members in refugee and migrant groups to get them across western borders[4]. No amount of extreme vetting as the President advocates will eliminate that risk, better processes can decrease it, but not eliminate it.

The conversation Americans should be having is how much risk is acceptable. Policy and law are not made in a vacuum. Homeland security wonks are not appointed philosopher kings, allowed to create national policy at will because there are other things Americans value alongside safety and security.

Americans need to have a continuing national conversation about those values, and about how much risk we’re willing to tolerate towards humanitarian ends. Using statistics like “one in 3.64 billion” as “empirical” proof that refugees pose little risk to Americans is misleading and a tool for shutting down the conversation. It serves no purpose other than leaving the brandisher of the statistic self-satisfied in their own intelligence, and the person on the receiving end silently indignant having not changed their mind. Ideally, leadership would come from our elected representatives on honest discussions of national values and acceptable risk- but it doesn’t seem likely that that will happen.


Note: This was originally published by Red Alert Politics on March 3rd 2017 under the title “1-in-3.64 billion chance of being killed by a refugee? Believe that at your own risk”

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