"(CNN) -- U.S. drone strikes in Pakistan have killed far more people than the United States has acknowledged, have traumatized innocent residents and largely been ineffective, according to a new study released Tuesday.
The study by Stanford Law School and New York University's School of Law calls for a re-evaluation of the practice, saying the number of "high-level" targets killed as a percentage of total casualties is extremely low -- about 2%."

from

http://www.cnn.com/2012/09/25/world/asia/pakistan-us-drone-strikes/