Psyche, Science, and Society

New estimate of Iraq violent mortality, 151,000, far lower than Lancet

January 9th, 2008

A new household survey in Iraq released today comes up with an estimate for violent mortality far lower than that by Burnham, Roberts and others in the Lancet last year. they estimate 151, 000 violent deaths. The study is available online from the New England Journal of Medicine. [I have not read the study yet but felt that I should post it as soon as possible.] Here is an article from MedPage Today on the study:

Violence-Related Mortality in Iraq from 2002 to 2006

By Peggy Peck

GENEVA, Jan. 9 — The latest audit of Iraq war deaths — combatants and civilians — puts the mortality toll at 151,000, which is about 75% lower than an estimate published more than a year ago.

The new estimate comes from the Iraq Family Health Survey Study Group, a joint project of the World Health Organization and the Iraqi government that did interviews in 9,345 households in about 1,000 locations across Iraq. The findings were published online today by the New England Journal of Medicine.

The total mortality was based on direct reporting of deaths by household respondents, and the authors said that “there are no better methods available to provide more accurate estimates of the death toll due to the humanitarian conflict in Iraq in the wake of the 2003 invasion.”

The Iraq Family Health Study was a representative study of 9,345 households that have been providing information on deaths since 2001. The new estimate was culled from surveys conducted in 2006 and 2007 with 1,086 household clusters that reported 1,325 deaths from January 2002 through June 2006.

But estimating deaths in a war zone is not an exact science and the authors said that when “underreporting was taken into account, the rate of violence-related death was 1.67 (95% uncertainty range: 1.24 to 2.30). This rate translates into an estimated number of violent deaths of 151,000 (95% uncertainty range: 104,000 to 223,000) from March 2003 through June 2006.”

In other words, the number of violent deaths could be as low as 104,000 or as high as 223,000 during those three years, but the most probable total was 151,000, said Mohamed Ali, Ph.D., a WHO statistician who was a member of the Iraq Family health Survey Study Group.

And even the high-end estimate of this survey was about 66% lower than the mortality estimate from Burnham et al (Lancet 2006; 368: 1421-8), which estimated that there were 601,027 violent deaths during the three years following the U.S. invasion of Iraq in March 2003.

But the Iraq Family Health Survey estimate was about three times higher than the deaths reported by the Iraq Body Count project, which reported 47,668 deaths.

“How is it that these numbers vary so widely, given that there can only be one true answer?” asked Catherine A. Brownstein, M.P.H., of Yale, and John S. Brownstein, Ph.D., of Harvard in an editorial that accompanied the survey results.

“The [Iraq Family Health Survey] study group does not directly address this question, but it deserves speculation,” the Brownsteins added. “The probable cause is that the techniques used to obtain the estimates differ radically from one another.”

The Iraq Body Count project crosschecks civilian deaths that are reported by a minimum of two independent sources against hospital and morgue records, as well as official figures. Moreover, it does not include deaths of combatants in its tally. It represents surveillance, not survey, and “should be treated as a reliable lower bound,” according to the editorialists.

The Burnham study used a method similar to that of the Iraq Family Health Survey but its overall sample involved only 1,849 households in 47 cluster areas, while the new survey included almost five times as many households and 20 times more regions or clusters.

And although all three surveys identify the same regions as high mortality areas — Anba, Babylon, Basra, Diyala, Nineveh, and Salahuddin — there were striking differences in the death rates in those areas reported by Burnham et al versus the Iraq Family Health Survey.

According to Burnham et al, the daily death rates in those regions for years 2003 to 2006 were 231, 491, and 925, respectively, versus 128, 115, and 126 for the same periods in the Iraq Family Health Survey.

All three surveys also agreed that Kurdistan was a low mortality area and Baghdad was a high mortality area. But although 54% of the deaths reported in the Iraq Family Survey and 60% of the deaths reported by the Body Count project occurred in Baghdad, only 26% of the deaths reported by Burnham et al occurred in Baghdad.

Finally, the authors concluded that even though their estimate was “substantially lower than that estimated by Burnham et al, it nonetheless points to a massive death toll in the wake of the 2003 invasion — and represents only one of the many health and human consequences of an ongoing humanitarian crisis.”

The survey was funded by the United Nations Development Group Iraq Trust Fund, the European Commission, and the WHO.

The study group members reported no potential conflicts of interest.

Here is the Abstract from the paper:

Violence-Related Mortality in Iraq from 2002 to 2006

Iraq Family Health Survey Study Group

ABSTRACT

Background Estimates of the death toll in Iraq from the time of the U.S.-led invasion in March 2003 until June 2006 have ranged from 47,668 (from the Iraq Body Count) to 601,027 (from a national survey). Results from the Iraq Family Health Survey (IFHS), which was conducted in 2006 and 2007, provide new evidence on mortality in Iraq.

Methods The IFHS is a nationally representative survey of 9345 households that collected information on deaths in the household since June 2001. We used multiple methods for estimating the level of underreporting and compared reported rates of death with those from other sources.

Results Interviewers visited 89.4% of 1086 household clusters during the study period; the household response rate was 96.2%. From January 2002 through June 2006, there were 1325 reported deaths. After adjustment for missing clusters, the overall rate of death per 1000 person-years was 5.31 (95% confidence interval [CI], 4.89 to 5.77); the estimated rate of violence-related death was 1.09 (95% CI, 0.81 to 1.50). When underreporting was taken into account, the rate of violence-related death was estimated to be 1.67 (95% uncertainty range, 1.24 to 2.30). This rate translates into an estimated number of violent deaths of 151,000 (95% uncertainty range, 104,000 to 223,000) from March 2003 through June 2006.

Conclusions Violence is a leading cause of death for Iraqi adults and was the main cause of death in men between the ages of 15 and 59 years during the first 3 years after the 2003 invasion. Although the estimated range is substantially lower than a recent survey-based estimate, it nonetheless points to a massive death toll, only one of the many health and human consequences of an ongoing humanitarian crisis.

More information on the Iraq Family Health Survey is available from their web site.

Entry Filed under: Iraq,Mortality,Public Health,Research Methods