Three recent official and sort-of-official comments on this issue (well, two comments and one non-comment):
A remarkable interview in the Financial Times with David Kilcullen, the Australian former adviser on counter-insurgency to General David Petraeus. Kilcullen's comments on the civilian casualties caused by US drone strikes in western Pakistan:
"They [the strikes] have an undeniable benefit, because we have disrupted AQ [Al Qaeda] operations and damaged AQ cells in Pakistan. But they have a negative strategic effect in that they incite Punjabi militancy, which is the biggest problem in Pakistani right now." Mr Kilcullen said the hit rate on drone attacks was "unacceptably low". He said the US had killed 14 mid-level or lower level al-Qaeda leaders since 2006 but the strikes had killed 700 civilians. "That's a hit rate of two per cent on 98 per cent collateral. It's not moral."
In a fascinating but uncritical "60 minutes" report on USAF drone operations, the officer in charge of such operations at a USAF base in Nevada was asked if there were ever mistakes (in targeting the strikes): "What if you get it wrong?"
"We don't [get it wrong]" was his response.
There are no journalists in Waziristan or the other areas of western Pakistan bordering Afghanistan. There are therefore little or no first-hand or otherwise authoritative reports from the ground on the effects of these strikes from remotely-piloted vehicles (UAVs). At a recent New York Times-convened discussion which I attended, Richard Holbrooke, the US Special Envoy for Afghanistan and Pakistan, with characteristic bluntness, refused to comment at all on the question of civilian casualties from these strikes.