The emerging field of conflict epidemiology offers a more accurate method to measure deaths caused during violent conflicts or wars that can generate more reliable numbers than before to guide decision-makers.
In February 2001 the Carter Center and the United States Institute of Peace (USIP), in collaboration with CARE (relief), Emory University and the Centers for Disease Control and Prevention (CDC), sponsored a meeting on "Violence and Health". The goals of the meeting were to determine the impact of violent conflict on public health and to advise public health training programs on means to enhance the work of public health professionals in working in violent conflicts.
Compiling or estimating the numbers of deaths caused during wars and other violent conflicts is a controversial subject. Historians often put forward many different estimates of the numbers killed during historic conflicts. What conflict epidemiology offers is a better methodology to more accurately estimate actual mortality rates during existing wars and conflict.
Iraq Conflict 2003
The subject of conflict epidemiology made headline news after a report of a survey was conducted by an American and Iraqi team of public health researchers. Data were collected by local Iraqi doctors and analysed by the faculty of the Johns Hopkins School of Public Health.
There is an extensive Wikipedia entry on this report here: Lancet surveys of casualties of the Iraq War
Burnham G, Lafta R, Doocy S, Roberts L., Mortality after the 2003 invasion of Iraq: a cross-sectional cluster sample survey. Lancet 2006;368:1421-8. 
Giles, James, Risking life and limb to count the war dead. New Scientist, no 2615, 1 August 2007.
Thieren, Michel, Health and foreign policy in question: the case of humanitarian action. Bulletin of the World Health Organization, vol 85, no 3.