Estimating the Impact of Drone Strikes on Civilians Using Call Detail Records

Image credit: Sr. Airman Christian Clausen


Drone strikes are a fixture of modern U.S. counterterrorism, often advertised as a “surgical,” less-risky alternative to ground operations. The effects of drone strikes, however, are less precise than proponents suggest. Using a dataset of over 12 billion call detail records from Yemen between 2010 and 2012, we show that the U.S. drone campaigns significantly disrupted civilian lives in ways that previous studies focused on “blowback violence” do not capture. Strikes cause large increases in civilian mobilityaway from affected areas and cause communication cascades among the same civilians. Displacement is both immediate and durable: Mobility of nearby individuals increased 24% on strike days themselves, and average distance from the strike region increased steadily for over a month, signifying prolonged displacement for thousands of individuals. Calling cascades emerged immediately after strikes and quickly reached users far beyond the affected area. Strikes disrupt civilian life whether or not they kill civilians, though the effects are larger after civilian casualties. Our findings suggest that even verycarefully-conducted drone campaigns will not have “surgical” effects, and encourage policy-makers to consider forms of collateral damage beyond casualties.

Under Review
Aidan Milliff
Aidan Milliff
Assistant Professor