The CIA appears to have cut civilian deaths from drone strikes in Pakistan: why can’t the US do the same in Yemen?

The CIA appears to have cut civilian deaths from drone strikes in Pakistan: why can’t the US do the same in Yemen, asks Owen Bennett-Jones | The Bureau of Investigative Journalism: 
In May 2013, faced with persistent reports of drones killing civilians, President Obama announced that no strike would be authorised unless there was: “near certainty that no civilians would be killed or injured.” It was, he said, “the highest standard we can set.”
The new rule seemed to make a difference. Before the speech the US had, according to Bureau of Investigative Journalism data, mounted 371 strikes in Pakistan that killed between 416 and 953 civilians.
Since the speech, 42 strikes have killed between 0 and six civilians. Or, put another way, there has been no confirmed civilian death as a result of a drone strike in Pakistan since the speech.
The drop in the number of strikes is not solely explained by the near-certainty standard constraining drone operators. The Pakistan government’s attitude has also affected the frequency of drone attacks.