In a rare public comment on drone strikes, President Obama told an online town hall in January that the drones had not caused "a huge number of civilian casualties."
When giving their own figures on civilian deaths, administration officials are often countering local reports. In March 2011, for example, Pakistanis including the country's army chief accused a U.S. drone strike of hitting a peaceful meeting of tribal elders, killing around 40 people. An unnamed U.S. official rejected the accusations, telling the AP: "There's every indication that this was a group of terrorists, not a charity car wash in the Pakistani hinterlands."
Unnamed U.S. officials told the Los Angeles Times last year that "they are confident they know who has been killed because they watch each strike on video and gather intelligence in the aftermath, observing funerals for the dead and eavesdropping on conversations about the strikes."
U.N. High Commissioner for Human Rights Navi Pillay said during a visit to Pakistan this month that there should be investigation of killings of civilians by drones and that victims should be compensated. The U.S. has given compensation to victims of airstrikes in Afghanistan but there are no reports of victims of drone strikes in Pakistan being compensated.
Since the various administration statements over the years were almost all quoted anonymously, it's impossible to go back to the officials in question to ask them about contradictions.
Asked about the apparent contradictions, National Security Council spokesman Tommy Vietor told ProPublica: "[W]e simply do not comment on alleged drone strikes."