Lancet surveys of Iraq War casualties

The Lancet, one of the oldest scientific medical journals in the world, published two peer-reviewed studies on the effect of the 2003 invasion of Iraq and subsequent occupation on the Iraqi mortality rate. The first was published in 2004; the second (by many of the same authors) in 2006. The studies estimate the number of excess deaths caused by the occupation, both direct (combatants plus non-combatants) and indirect (due to increased lawlessness, degraded infrastructure, poor healthcare, etc.).

The first survey^[1] published on 29 October 2004, estimated 98,000 excess Iraqi deaths (with a range of 8,000 to 194,000, using a 95% confidence interval (CI)) from the 2003 invasion and subsequent occupation of Iraq to that time, or about 50% higher than the death rate prior to the invasion. The authors described this as a conservative estimate, because it excluded the extreme statistical outlier data from Fallujah. If the Fallujah cluster were included, the mortality estimate would increase to 150% over pre-invasion rates (95% CI: 1.6 to 4.2).

The second survey^[2]^[3]^[4] published on 11 October 2006, estimated 654,965 excess deaths related to the war, or 2.5% of the population, through the end of June 2006. The new study applied similar methods and involved surveys between 20 May and 10 July 2006.^[4] More households were surveyed, allowing for a 95% confidence interval of 392,979 to 942,636 excess Iraqi deaths. 601,027 deaths (range of 426,369 to 793,663 using a 95% confidence interval) were due to violence. 31% (186,318) of those were attributed to the US-led Coalition, 24% (144,246) to others, and 46% (276,472) unknown. The causes of violent deaths were gunshot (56% or 336,575), car bomb (13% or 78,133), other explosion/ordnance (14%), air strike (13% or 78,133), accident (2% or 12,020), and unknown (2%).

The mortality estimates in the Lancet surveys are higher than in several other reports, including those of the Iraqi Health Ministry and the United Nations, as well as other household surveys such as the Iraq Living Conditions Survey and the Iraq Family Health Survey. The 2007 ORB survey of Iraq War casualties estimated more deaths than the Lancet, though it covered a longer period of the conflict.^[5]^[6] The Lancet surveys have been supported by some journalists, governments, epidemiologists and statisticians, and been met by criticism and disbelief from other journalists, governments, epidemiologists and statisticians.^[7]

20 November 2004. Criticism and suggestions by peer reviewer Professor , MRC Biostatistics Unit, Cambridge CB2 2SR, UK, chair of the Royal Statistical Society's Working Party on Performance Monitoring in the Public Services. Calls scientific method "generally well described and readily repeatable", but says "[p]articular attention is needed to the methodology for randomly selecting the location(s) of cluster(s) within governorates. Roberts and colleagues describe this rather too succinctly". Suggests additional information be included so that more precise multipliers (to obtain the final estimate) can be applied. Discusses an example hypothetical circumstance incorporating said information, regarding airstrike deaths and collateral damage, under which over-counting could occur due to population density variances among cluster representations.^[18]

Sheila Bird

26 March 2005. Criticism by Stephen Apfelroth, Department of Pathology, Albert Einstein College of Medicine. Criticizes "several questionable sampling techniques that should have been more thoroughly examined before publication" and lists several flaws, including a "fatal" one, that "In such a situation, multiple random sample points are required within each geographic region, not one per 739,000 individuals."

[19]

26 March 2005. Response by et al. to Apfelroth. Acknowledges flaws, but says "the key public-health findings of this study are robust despite this imprecision. These findings include: a higher death rate after the invasion; a 58-fold increase in death from violence, making it the main cause of death; and most violent deaths being caused by air-strikes from Coalition Forces. Whether the true death toll is 90,000 or 150,000, these three findings give ample guidance towards understanding what must happen to reduce civilian deaths. ... Before publication, the article was critically reviewed by many leading authorities in statistics and public health and their suggestions were incorporated into the paper. The death toll estimated by our study is indeed imprecise, and those interested in international law and historical records should not be content with our study. We encourage Apfelroth and others to improve on our efforts. In the interim, we feel this study, as well as the only other published sample survey we know of on the subject, point to violence from the Coalition Forces as the main cause of death and remind us that the number of Iraqi deaths is certainly many times higher than reported by passive surveillance methods or in press accounts."^[20]

Les Roberts

. An overview of many casualty estimates.

Casualties of the Iraq War

ORB survey of Iraq War casualties

Iraq Family Health Survey

Elisabeth Rosenthal, , International Herald Tribune via the New York Times, 29 October 2004.

"Study Puts Iraqi Deaths of Civilians at 100,000"

Sarah Boseley, , The Guardian, 29 October 2004.

"100,000 Iraqi civilians dead, says study"

"100,000 Iraqis Dead: Should We Believe It?", ZNet, 3 November 2004.

Stephen Soldz

Jamie Doward, , column in The Guardian, 7 November 2004.

"The Lancet and the bodies in question"

Joseph Choonara, , interview of Les Roberts, Socialist Worker, 23 April 2005.

"Counting the dead in Iraq"

Les Roberts, , American Friends Service Committee, 26 October 2005.

"100,000 deaths in Iraq: A year later"

Les Roberts at the London School of Hygiene & Tropical Medicine, on 13 April 2005; uploaded in https://www.youtube.com/watch?v=o5vD_Ub2K_c on 25 October 2006.