From here.
Specifically, Gen. Petraeus is expected to say there’s been a 75% drop in sectarian attacks, a 56% drop in overall attacks, and a 17% drop in civilian casualties...
The intelligence community has its own problems with military calculations. Intelligence analysts computing aggregate levels of violence against civilians for the NIE puzzled over how the military designated attacks as combat, sectarian or criminal, according to one senior intelligence official in Washington. “If a bullet went through the back of the head, it’s sectarian,” the official said. “If it went through the front, it’s criminal.”
As Ilan Goldenberg summarized, “So to recap. The violence numbers do not include: 1) Sunni on Sunni violence. 2) Shi’a on Shi’a violence 3) Car bombs 4) Getting shot in the front of the head.”