Introduction

There has been enormous interest and debate over the newly published Lancet Iraqi mortality estimate of 655,000 excess deaths since the invasion, 601,000 of them from violence (and including combatants with civilians). Even the latter estimate is some 12 times larger than the IBC count of violent civilian deaths reported in the international news media, which stands at something under 50,000 for the same period (although the IBC figure for this period is likely to considerably increase with the addition of as yet unprocessed data). The new Lancet estimate is also almost the same degree higher than any official records from Iraq. This contrast has provoked numerous requests for comment, and these are our first observations.

The researchers, and in particular their Iraqi colleagues who carried out the survey, should be commended for undertaking it under dangerous circumstances and with minimal resources. Efforts like theirs have consistently highlighted that much more could be done by official bodies, such as the US and UK governments, to assess the human suffering that has resulted from the invasion and occupation of Iraq.

However, our view is that there is considerable cause for scepticism regarding the estimates in the latest study, not least because of a very different conclusion reached by another random household survey, the ILCS, using a comparable method but a considerably better-distributed and much larger sample. This latter study gave a much lower estimate for violent deaths up until April 2004, despite that period being associated with the smallest number of observed deaths in the latest Lancet study.

Additionally, claims that the two Lancet studies confirm each other's estimates are overstated. Both the violent and non-violent post-invasion death estimates are actually quite different in the two studies.

What emerges most clearly from this study is that a multi-methodological approach and much better resourced work is required. Substantially more deaths have occurred than have been recorded so far, but their number still remains highly uncertain.

We also take the view that far more recognition should be accorded the many other courageous people in Iraq, be they Iraqi or international journalists, hospital, morgue, and other officials, or relief workers, who are endeavouring to keep the world informed on the country's plight. Far too many have had to pay the highest possible price for their efforts. Ignorance of this catastrophic war would be far less endemic if their day-by-day contribution were consistently given the exposure it merits. The daily toll on civilian lives resulting from the Iraq war should be front-page news in the countries that instigated it, not inside-page news.

The Lancet estimate

In October 2004 the Lancet published a random cluster sample survey estimating that 98,000 Iraqis had died as a result of the invasion up to that point (an 18-month period), and that 57,600 of these deaths were from violence. The October 2006 study comes from the same research team and provides an estimate for the 40-month period from March 2003 to June 2006 of 655,000 excess deaths, 601,000 of them from violence. The data presented do not distinguish between civilian and combatant deaths. Since IBC's work is confined to violent civilian deaths, we make no further comment on Lancet's non-violent death estimates.

The Lancet researchers visited 47 neighbourhoods and conducted interviews in 40 adjoining households in each neighbourhood. About 1,800 households containing 12,000 Iraqis were surveyed. These households reported a total of 302 violent deaths, each of which has been multiplied by two thousand to provide an estimate of how many of Iraq's estimated 26,000,000 population would have died if this proportion of deaths were representative of the country as a whole.

The study's central estimate of 601,000 violent deaths is exceptionally high. Even its lower bound 95% confidence interval of 426,000 violent deaths is shockingly large. If numbers of this magnitude are anywhere near the truth, then they reveal a disaster far greater than most could have conceived, and one which appears inconsistent with a considerable amount of other information that has emerged over the last three and a half years. Before any firm conclusions are drawn on the basis of this study, five important (and extremely anomalous) implications of the data presented by the Lancet authors require examination.