Bird Sheila M, Fairweather Clive B
MRC Biostatistics Unit, Cambridge CB2 2SR.
Int J Epidemiol. 2007 Aug;36(4):841-6. doi: 10.1093/ije/dym103. Epub 2007 May 21.
Military fatalities occur in clusters, and causes differ between theatres of operation or within-theatre over time.
Based on around 500 coalition deaths, identify major causes in Iraq and Afghanistan. For consecutive periods (1: May 1 to September 17, 2006, 2: September 18, 2006 to February 4, 2007), ascertain UK and others' numbers deployed to compare fatality rates per 1000-personnel years. Take account of clustering: deaths per fatal improvised explosive device (IED) incident, and in making short-term projections for Afghanistan.
Cause and date of coalition deaths in Iraq and Afghanistan are as listed in http://www.iCasualties.org, where each death is designated as hostile or non-hostile. Numbers deployed in 2006 were available for UK and Canada, and for US to Iraq.
Out of 537 coalition fatalities in Iraq in 2006 to September 17, 2006, 457 (85%) were hostile, but only half were in Afghanistan (October 2001 to September 17, 2006: 52%, 249/478). Air losses accounted for 5% fatalities in Iraq, but 32% in Afghanistan. IEDs claimed three out of five hostile deaths in Iraq, only a quarter in Afghanistan. Deaths per fatal IED incident averaged 1.5. In period 1, 50/117 military deaths in Afghanistan were UK or Canadian from 6750 personnel, a fatality rate of 19/1000/year, nearly four times the US rate of 5/1000/year in Iraq (based on 280 deaths). Sixty out of 117 fatalities in Afghanistan occurred as clusters of two or more deaths. In period 2, fatality rates changed: down by two-thirds in Afghanistan for UK and Canadian forces to 6/1000/year (18 deaths), up by 46% for US troops in Iraq to 7.5/1000/year (416 deaths).
Rate, and cause, of military fatalities are capable of abrupt change, as happened in Iraq (rate) and Afghanistan (rate and cause) between consecutive 140-day periods. Forecasts can be wide of the mark.
