A new study is refuting claims that pilot-less drones carry out more precise attacks than conventional aircraft. Speaking to The Guardian, Larry Lewis of the Center for Naval Analyses says he found that remote-controlled drones caused 10 times more civilian casualties than piloted warplanes over the course of one year in Afghanistan. Lewis says his findings are based on classified military files covering mid-2010 to mid-2011, the most intense period for U.S. air strikes during the Afghan war.