In the battle of Fallujah, U.S. military commanders say they killed between 1,000 to 1,200 or 1,200 to 1,600 enemy fighters, depending on your news source. However, embedded correspondents in the field reported that Army and Marine Corps units found fewer enemy bodies in Fallujah than they expected. How exactly does the military determine its body counts?
As a matter of policy, the U.S. military does not officially track enemy killed in action. But the headquarters responsible for an individual campaign—the 1st Marine Expeditionary Force, in the case of Fallujah—often does compile such figures, which explains why they sometimes appear in the papers. After a campaign, the headquarters will pull together reports from every unit in the fight to create one big estimate of the enemy's casualties for the entire operation.
Individual units send in several kinds of reports. The lowest-tech—and most reliable—way to determine enemy KIA is to physically count dead enemy corpses. After a military unit seizes an area, such as Fallujah, the troops will report to their headquarters the number of bodies they see left behind. However, this number usually undercounts the dead because most militaries try not to leave their fallen on the ground. This count also misses wounded soldiers who were evacuated for medical treatment and died later, and enemy soldiers directly hit by high-explosive ordnance, such as an artillery shell or 2,000-pound bomb. In such instances, there's little left to count when the battle's over.
The folks at headquarters also rely on "contact reports" from engaged units. For example, an infantry platoon fighting insurgents will radio (or sometimes e-mail) its headquarters to let them know about the fight and, once done, about the outcome. In addition to data like the time and place of the engagement, contact reports usually include a quantification of enemy casualties, estimated by the platoon commander (or another battlefield leader) based on what he and his troops saw first-hand during the fight. So, if a soldier shot an insurgent and believes he killed him, the platoon commander might include the death in his contact-report tally, even if the unit is unable to physically search the battleground and confirm it when the conflict ends. If his troops destroyed an enemy vehicle, the commander will usually estimate the number of dead inside and include them, too. (Such estimates are often based on the usual size of a given vehicle's crew.) A Marine Corps colonel in Iraq said such reports were fairly reliable in Fallujah, because of the close range of the fighting—but were still inexact. "A report of '20 [enemy KIA]' may be anywhere from 15 to 25" in reality, he said, because the stress and fog of war can obscure what troops see in battle.
The headquarters body counts also include enemy troops (and often civilians) killed by artillery bombardments or airstrikes. Although shooters in these situations can't always see their targets, intelligence analysts rely on observations of the target before and after the strike. Usually, such information is relayed by the person observing the target and calling for the artillery. In Fallujah, military analysts also relied on the camera feeds from unmanned aerial vehicles flying constantly over the city. Analysts watch buildings carefully over the course of a day to see how many people went in and out and guess how many were in when a particular bomb hit. Intelligence staffs at varying levels of command also pore over these "bomb damage assessments" to correlate them and produce a total number of KIA that comes as close as possible to the true number.
The U.S. military as a whole doesn't formally compile these numbers because it is reluctant to use them to measure its success or failure in battle. On Monday, the operations officer for the Marines in Fallujah told reporters, "I don't really like to ever, and nor will I ever, go through enemy killed in action." This reticence can be traced back to the Vietnam War and the significant problems that emerged during that conflict when Defense Secretary Robert McNamara overemphasized body counts as a metric of success.
Explainer thanks John Pike of the think tank GlobalSecurity.org, and 1st Lt. Catherine Wallace of U.S. Central Command.