Search Findings
Our systematic review and non-structured search together yielded a total of 19 relevant studies, surveys and reports at first pass. Of these, 6 studies were sourced through the systematic search and 13 through the non-structured searches. One study proved ineligible because the research objective was unrelated to determination of Iraqi deaths [9]. A multiple indicators cluster survey was also excluded because its findings were limited to infant and child mortality [10]. A report from the US Department of Defense [11] was removed as its estimates were sourced from other databases and no information was provided on the methodology; additionally, these figures are referenced in the dataset for the Brookings Institution, a study included in this review. In addition, a review done by the Los Angeles Times [12] was excluded to reduce the possibility of duplicate reporting, as it has been incorporated as a data source for one of the broader studies included in this review [13]. Information recently released by the American Civil Liberties Union was excluded because it was not a comprehensive mortality study and only provided information on fatalities that were reported to the US government for compensatory claims [14]. Lastly, a poll conducted by D3 Systems was excluded because it included any physical harms resulting from violence, not just deaths since the start of the war [15]. Our completed review includes a total of 13 studies.
Study Characteristics
The 13 studies that we included are separated into two general categories: population-based studies and passive reporting. The passive data is further sub-divided according to whether they were published or unpublished (i.e. referenced only by secondary sources, usually the media). Tables 1, 2 and 3 [see Additional file 1] present study characteristics under each categorization. Each of the studies differed in terms of the mortality estimates, study populations, time period and research methodologies used, contributing to a broad range of mortality rates.
The time period for reported deaths ranged from 42 days, generally the duration of the 'war' as declared by the US government, to ongoing figures updated monthly or weekly. The study population ranged from only civilians/non-combatants to both combatants and civilians/non-combatants, included and excluded Kurdish regions, and reported deaths due to violence or from all causes.
Study Quality
Only 5 studies clearly relied on a population-based approach; all were retrospective household surveys [16–20]. We found that all 5 studies provided appropriate details on representative sampling and used broad cluster sampling. All 5 studies reported on their methods of randomization in sampling and all used systematic random sampling to allocate clusters. All 5 studies reported on the response rates of households. Two of the studies attempted to ensure accuracy of the deaths by requesting death certificates [16, 18]. Finally, 1 study reported revisiting households to confirm initial findings and found that there was a discrepancy between initial under-5 deaths reported and the larger number identified in the revisit [17, 21].
Individual Study Results
As there was a broad range of methodologies used, there are similarly a broad range of daily death rates, CMR and VMR totals. The average daily mortality rates ranged from 48 to 759, the Iraq Body Count (IBC) representing the lowest estimate and the Opinion Research Business (ORB) survey representing the highest. The cause-specific MR attributable to violence ranged from 0.64 to 10.25, with the IBC and ORB studies again representing each of the limits. Table 4 [see Additional file 2] presents detailed study outcomes.
Individual Studies
Below, we summarize the key details from each study, separated according to population-based studies and passive reporting, and whether the data was published or unpublished.
Population-based Studies
Roberts et al, 2004 (period of data collection March 20, 2003–September (15), 2004) [16]
This cluster random-sample survey of households throughout Iraq aimed to determine mortality of Iraqis before and after the 2003 invasion. Thirty-three cluster starting points were allocated among Governorates by probability proportional to size (PPS). In the sampling frame, adjacent Governorates (matched for pre-invasion violence and economic development) were paired to reduce travel time and the potential risk to study team members. Thirty households were then selected within each cluster. The starting household in the cluster was randomly selected using a GPS navigation system; research teams visited households adjacent to the starting households until a total of 30 were surveyed. Individuals were included in the survey if they had been residents of the household during the two preceding months. Research teams included medical doctors, both male and female, and all members spoke both English and Arabic. Each household was asked for information on births, deaths and visitors staying in the household for more than 2 months. This information was requested both for the period before (January 2002 to March 2003) and after (March 2003 to September 2004) the invasion. For reported deaths, interviewers requested copies of death certificates for two in each cluster, so as not to compromise researcher safety, as persistence may have been interpreted suspiciously. Death certificates were produced in 81% of the cases requested.
A total of 33 clusters, 988 households and 7,868 residents were chosen; five households refused to participate and in those clusters with proper absentee records, 872 households were visited (64 absent). A cluster located in Falluja yielded extremely high violent death rates, was considered an outlier and thus conservatively excluded in many of the analyses. The total mortality estimates include both civilians and combatants for all causes. The study estimates that there was an average of 98,000 excess deaths since the invasion (95% CI, 8,000–194,000). Approximately 51% were estimated to be attributable to violent causes, or 24% if Falluja is excluded. Based on these figures, there are an estimated 180 excess deaths per day (15–356). Study authors reported a crude mortality rate post-invasion of 12.3 (95% CI, 1.4–23.2) per 1,000 population per year over the entire study period, including Falluja, compared with a pre-invasion rate of 5.0 (95% CI, 3.7–6.3). Excluding Falluja, the total crude mortality rate post-invasion was 7.9 (95% CI, 5.6–10.2).
The Iraq Living Conditions Survey, 2004 (period of data collection March 20, 2004–May (31), 2004) [17]
The Iraq Ministry of Planning and Development Corporation, in partnership with the United Nations Development Program (UNDP), commissioned a multi-indicator household survey in 2004. The study was conducted by the NGO FAFO. Interviewers administered two questionnaires: 1) to recognized head of households on issues related to a variety of indicators, including housing and infrastructure, household economy, basic demography, and the education, health (including household deaths), and labour force characteristics of the household members; and, 2) to household women aged 15 to 45 on issues related to reproductive and child health. The survey was conducted in both Arabic and Kurdish. Although the survey was created in English, it was back-translated for verification. Authors estimated that the detailed survey took between 60 to 102 minutes per household. The gender mix and profession of those administering the questionnaire was not indicated.
The study was a multi-stage cluster sample survey. Cluster starting points were allocated among Governorates using a mixture of PPS and explicit stratification so as to provide various stratum-specific estimates (e.g. by Governorate and urban versus rural), based on population data from census or local statistics offices. Ten households within each cluster were then selected by segmentation (selection by PPS of a sufficiently small population unit, exhaustive listing of households in the unit, and systematic random sampling within this list).
The results of the surveys were sent to the Governorate office for registration and inspection, to Baghdad for coding, data entry and quality control, and then to FAFO's headquarters in Norway for further quality reviews. Where required, additional re-interviewing was conducted in the field.
A total of 21,668 households were surveyed from across Iraq, including all Kurdish areas. The total mortality estimates include both civilians and combatants. The ILCS estimates there were approximately 24,000 (95% CI, 18,000–29,000) war related deaths (presumably due to violence) since March 2003, as determined by the number of persons reported dead or missing in each of the households due to violent causes. Based on these figures, the violent death rate is 54 per day (41–66) and the violent mortality rate is 0.74 per 1,000 per year (95% CI, 0.55–0.89). The study investigators found discrepancies with a higher number of deaths reported when a sample of households was revisited [21].
Burnham et al, 2006 (period of data collection March 20, 2003–July (15), 2006) [18, 22]
This study was intended to update the mortality figures reported by a previous study published in 2004 [16]. For this study, researchers conducted a cluster random-sample survey of households throughout Iraq. Fifty clusters of 40 households, estimating 8 members per household, were allocated among Iraq's Governorates using PPS. A further stage of PPS sampling allocated clusters to administrative units within each Governorate. Within each administrative unit, one main street and one residential street crossing this main street were randomly selected, and the starting household for the cluster selected randomly among all households along this residential street. Researcher teams then visited adjacent households until 40 households were surveyed. Individuals were included in the survey if they had been residents of the household during the three preceding months. Research teams were comprised of trained medical doctors, both male and female, who spoke both English and Arabic. Each household supplied information concerning births, deaths and in/out migration before and after the invasion. Wherever possible and where interviewer safety was not deemed to be compromised, the cause of death and a copy of the death certificate were requested for verification.
A total of 47 clusters, 1,849 households and 12,801 members were included in the final data analysis; 3 clusters were not completed due to miscommunication and other security issues, and were excluded from the final sample. Results were based on comparing the death rates in all households surveyed for the period before invasion (January 2002 to March 2003) and in the period after (March 2003 to July 2006) to determine the total excess deaths due to the war, meaning those deaths above the pre-invasion rates. Mortality estimates include both civilians and combatants for all causes. The study estimates that there were 654,965 excess deaths since the invasion (95% CI, 392,979 to 942,636). Of these, 601,027 (95% CI, 426,369 to 793,663) were attributable to violent causes. Based on these figures, there are an estimated 540 deaths per day (95% CI, 324 – 777). Study authors reported a crude mortality rate of 5.5 (95% CI, 4.3–7.1) in the period pre-invasion, 13.2 (95% CI, 10.9–16.1) per 1,000 population per year over the entire study period, and a rate of 19.8 (95% CI, 14.6–26.7) for the last year from June 2005 to June 2006. The overall cause-specific mortality rate due to violence is 7.2 per 1,000 per year.
Opinion Research Business, 2007 (period of data collection March 20, 2003–August (15), 2007) [19]
The British polling agency Opinion Research Business (ORB), in partnership with their Iraqi fieldwork agency, has been tracking opinion in Iraq since 2005 and conducted a poll of the population in August 2007 to determine the impact of the ongoing conflict.
ORB used a multi-stage random probability sample in 15 of the 18 governorates to derive a representative sample of 1,720 households. Karbala and Al Anbar governorates were excluded for security reasons and Irbil refused to grant a permit to conduct the survey. 1,499 in the sample agreed to respond to the question. The poll asked an adult over the age of 18 in each household: "How many members of your household, if any, have died as a result of the conflict in Iraq since 2003 (i.e. as a result of violence rather than a natural death such as old age)? Please note that I mean those who were actually living under your roof." The survey was conducted through face-to-face interviews. No further information regarding the study methods was provided.
Respondents replied by stating the number of individuals in the household that have died due to violence since March 2003: 78% stated none; 16% stated one; 5% stated two; 1% stated three; and, 0.002% stated four or more. ORB based their total mortality calculations on the 2005 census information, which assumes that there are a total of 4,050,597 households throughout Iraq. They estimate that 1,220,580 [margin of error +/- 2.5% equals a range of 733,158–1,446,063] deaths due to violence have occurred since March 2003. Based on these estimates, there are 759 deaths per day (range 456–899) and the violent mortality rate is 10.25 per 1,000 per year (range 6.15–12.16).
Iraq Family Health Survey, 2008 (period of data collection March 20, 2003–June (15), 2006) [20]
The Iraq Family Health Survey was conducted in 2006 and 2007 by federal and regional ministries in Iraq, and the Central Organization for Statistics and Information Technology (COSIT), with technical support provided by the World Health Organization. It was a cross-sectional, nationally representative household survey that estimated morbidity and mortality rates from January 2002 through June 2006, for both pre- and post-invasion periods.
The study design was a two-stage stratified sample survey of households. Excluding Baghdad, each of 17 of the 18 governorates in Iraq were divided into 3 sampling domains; Baghdad was divided into 5 sampling domains, for a total of 56 sampling domains in the survey. Each of the 56 domains was further stratified into 18 clusters and 10 households were selected from each cluster using a linear random systematic sampling. The total target sample was 10,080 households. However, cluster sizes in the Baghdad-Karkh, Anbar and Nineveh domains were increased to account for the liklihood that some clusters would be inaccessible due to insecurity. Following this increase, a total of 1,086 clusters and 10,860 households were selected to be surveyed.
115 clusters in Anbar, Baghdad, Wasit and Nineveh were not surveyed due to insecurity. Mortality estimates for these areas were imputed using data from the Iraq Body Count to determine the ratio of death rates relative to other comparable high mortality provinces. Due to the exclusion of these areas, 9,710 households were visited and 9,345 interviews were conducted for a total response rate of 96.2%. The interview teams were comprised of both men and women and some of the female interviewers were doctors or other health professionals.
Three questionnaires, translated into both Arabic and Kurdish, were administered to three different members of each household regarding mental health, reproductive health, and other general questions. Interviewers asked for information on each household death that occurred during the study period, including sex, age, time and place of death, as well as the primary cause, as reported by the respondent. Questionnaires and forms in each completed cluster in the South/Centre of Iraq were sent to the Federal Ministry of Health in Iraq for verification; incorrect or incomplete forms were sent back to the respective governorates. Data was double entered and verified. Death certificates were not requested for verification. Design weights were calculated to adjust for different household sampling selection probabilities as well as non-responses.
Crude and cause-specific mortality rates were calculated by comparing the exposure times (to the nearest month) to the risk of death for the living and deceased in each household between for the pre-invasion period (January 2002 to February 2003) and post-invasion periods (March 2003 to June 2006). Estimates for violent deaths post-invasion accounted for survey sampling errors, including adjusting for the missing clusters, underreporting, and projected population figures due to migration.
There were a total of 61,636 people living in the households that were sampled. After adjusting for the rates in excluded clusters, the crude death rate prior to the invasion for all of Iraq was calculated to be 3.17 [95% CI, 2.70–3.75] per 1,000 person years; the rate post-invasion was 6.01 [95% CI, 5.49–6.60] per 1,000 person years. The cause-specific death rate due to violence was 0.10 [95% CI, 0.04–0.32] and 1.09 [95% CI, 0.81–1.50] per 1,000 person years, respectively; however, after accounting for sampling errors and adjusting for missing clusters, the rate was projected to be 1.67 [95% CI, 1.24–2.30]. Authors estimate that the number of deaths due to violence from March 2003 through June 2006 is 151,000 [95% CI, 104,000 to 223,000]. Based on this, the number of violence-related deaths per day is approximately 126 [95% CI, 87–186].
Passive reporting
Published Studies
Conetta C, Project on Defense Alternatives Research Methods (PDAR), 2003 (period of data collection March 19, 2003–May 1, 2003) [13]
The PDAR conducted an analysis and synthesis of data reported on Iraqi deaths, including journalistic surveys of casualty incidents, hospitals, burial sites and graveyards and battlefield eyewitness accounts from embedded journalists and military personnel. Totals are based on data extrapolation for all of Iraq, based on the database of compiled reports and incidents.
Civilian casualty data was generally compiled from media surveys and reports, including those by the Associated Press, Knight-Ridder and the Los Angeles Times and supplemented by NGO studies, such as the Campaign for Innocent Victims in Conflict (CIVIC), as well as other media reports of casualty incidents based on eyewitness accounts from hospital personnel, aid workers, and the families of the dead. Mortality estimates for combatants are derived largely from embedded journalists and interviews with military personnel on both sides and some estimates based on artillery power projections. PDAR has reported total figures for all deaths and those separately for both non-combatant and combatants. The authors do not provide a specific time period; all estimates are for deaths that occurred, generally, "during the war", presumably the period from invasion to the official declaration by President Bush that combat had ceased (May 2003).
The PDAR estimates that a total of 12,950 Iraqis were killed in the war (+/- 2,150 a range of 15,100–10,800). Of these, 9,200 (+/- 1,600 a range of 10,800–7,600) were combatants and 3,750 (+/- 500 a range of 4,250–3,250) were non-combatants. However, PDAR has recognized that in some cases there may be overlap and an inability to distinguish precisely between combatant and non-combatant deaths. Based on these figures, the total daily death rate would be 308 per day (range, 287–360) with a crude mortality of 4.15 per 1,000 per year (range, 3.46–4.84); separated out, the rate for combatants would be 219 deaths per day (range, 181–257) with a crude mortality rate of 2.95 (range, 2.43–3.46) and non-combatants 89 deaths per day (range, 77–101) and a cause-specific mortality rate due to violence of 1.20 (range, 1.04–1.36) per 1,000 per year.
United Nations Assistance Mission for Iraq (UNAMI), December 2006 (period of data collection May 1, 2006–December 31, 2006) [23]
UNAMI is a centralised information sharing group which supports the UN's continued involvement in Iraq following the conclusion of the Oil for Food program.
The UNAMI Human Rights Office produces monthly reports identifying a series of current and ongoing rights violations as well as recommendations intended to mitigate the impacts. Included in these reports are total per-period deaths. Mortality figures are determined by combining the deaths reported by the Ministry of Health (MOH) and the Medico-Legal Institute of Baghdad (M-LIB). The MOH derives their reports from mortality figures received by all hospitals in Baghdad and other Governorates, with the exception of Kurdistan. The M-LIB totals are based on bodies brought to the morgue. The reported totals are for civilian deaths only and are almost entirely due to violence (with the exception of approximately 5–6% of the M-LIB figures).
UNAMI reported 25,847 total deaths in reports during the period of May to December, 2006. Although reports are also available from July 2005 to April 2006, they have been excluded for purposes of this review due to gaps in data and inconsistently reported methodology. In addition, the quarterly report for January to March 31, 2007, states that the Iraqi Government declined to provide access to the Ministry of Health's overall mortality estimates for this period. Based on the total deaths reported between May and December 2006, the number of deaths per day is approximately 106 and the cause-specific mortality rate attributable to violence is 1.42 per 1,000 per year.
The Brookings Institution, January 2008 (period of data collection May, 2003–December (15), 2007 and January 16, 2008) [24]
The Brookings Institution (BI) is an independent research organization that analyzes US national public policy issues. The 'Iraq Index' report is prefaced by stating that, generally, data is derived from the US government, NGOs and media reports, with only a small amount of information coming from Iraqi sources. Some of the data also includes further models by the BI.
The military and police mortality data referenced the Iraq Minister of the Interior, military personnel and media reports as information sources. The total number of Iraqi military and police deaths reported from June 2003 to January 16, 2008 is 7,792.
Data for civilian deaths was based on figures provided by the Iraq Body Count for the period from May 2003 to December 2005. This data was increased by a factor of 1.75, to account for the difference in casualty estimates noted between the IBC and Iraqi Ministry of the Interior for this period. The Brookings Institution conducted a separate study of the crime rate and estimated that approximately 23,000 murders had occurred throughout Iraq; the IBC and crime data were combined for a monthly estimate from May 2003 to December 2005 (44, 265). From the period of January 2006 to December 2006 mortality figures from UNAMI were totaled (34,452). Estimates for the period from January to December 2007 were based on U.S. State Department Weekly Status Report, September 12, 2007 and press briefings (18,300). The entire period civilian mortality estimate is based on a sum of these numbers and totals approximately 97,017.
Based on this information, the military and police daily mortality rate was approximately 5 deaths per day with a cause-specific MR due to violence of 0.06; the death rate for civilians was 57 deaths per day and cause-specific MR due to violence of 0.77 per 1,000 per year.
Iraq Body Count, January 2008 (period of data collection March 20, 2003–January 17, 2008) [25]
The Iraq Body Count (IBC) is the source most often referenced by coalition-forces politicians for Iraqi mortality estimates [26]. The IBC maintains a publicly accessible database of civilian deaths due to violence and increasing lawlessness resulting from the war, based on online surveys and compilation of media-reported deaths. Totals are based on mortality figures reported by online English language media agencies, designated from a list that meets IBC determined baseline standards and which are validated by at least two independently reported sources. Where discordant figures are reported, a range of deaths is provided by IBC. Although all figures are checked by two IBC staff and the original compiler of the data, the accuracy ultimately relies both on deaths actually reported by the media and on the rigor of the reporting agency. As such, IBC has acknowledged that total figures reported are likely underestimated [27].
As of mid-January 2008, the IBC reported an average of 84,333 Iraqi civilian deaths (range 80,621 to 88,044). Based on this figure for approximately a 1,764 day period, the average death rate would be estimated at 48 deaths per day (range 46 to 50) and the cause-specific MR due to violence is 0.64 per 1,000 per year (range 0.61 to 0.67).
Just Foreign Policy, January 2008 (period of data collection March 20, 2003–January 17, 2008) [28]
Just Foreign Policy (JFP) is an independent organization that promotes reformation of U.S. foreign policy. The group keeps an ongoing and continually updated record of Iraqi civilian deaths due to the U.S. invasion, intended to be a "daily rough estimate" and not a scientific study.
JFP estimates are based on a combination of the results of the Burnham et al. study and the Iraq Body Count. Mortality estimates are calculated according to the following formula: [Burnham et. al estimate as of July 2006] × [(Current IBC Deaths)/(IBC Deaths as of July 1, 2006)] As of mid-January, JFP projected that there were 1,168,058. Based on this, there are approximately 662 deaths per day and the mortality rate is 8.95 per 1,000 per year.
Unpublished Studies
The People's Kifah, 2003 (period of data collection March 20, 2003–October (15), 2003) [29, 30]
The People's Kifah, an Iraqi political organization, is reported to have conducted a population-based study in September and October 2003. Volunteers went into villages, towns and cities across Iraq in 14 Governorates, excluding Kurdish areas, to collect death statistics and information from individuals and hospitals. The survey also included interviews with grave-diggers and other eyewitness accounts. As the actual survey is unpublished, figures are derived from media reports on communications and statements sourced from the organization's spokesman, Dr. Muhammad al-Obaidi [30]. Unfortunately, the survey is reported to have discontinued due to the kidnapping of one of the workers.
The People's Kifah reported 37,137 civilian deaths due to violence during the seven months from March to October 2003. Therefore, the daily death rate is 177 and the cause-specific MR due to violence is 2.39 per 1,000 per year.
Iraqiyun, 2005 (period of data collection March 20, 2003–July 11, 2005) [31]
Iraqiyun is a humanitarian organization lead by Dr. Hatim al-Alwani. The actual study produced by the organization is unpublished, therefore total deaths are based on press reporting of statements made by al-Alwani which have implied that the study may have been a population-based study. Iraqiyun figures are based on reports from hospitals across the country and information obtained from relatives and families of the deceased.
On July 12, 2005, the organization reported that 128,000 Iraqis had died since the start of the war. Based on this figure, there are 152 deaths per day and a cause-specific mortality rate due to violence of 2.03 per 1,000 per year.
Iraq Ministry of Health, 2006 (period of data collection March (20), 2003–November (30), 2006) [32]
In November 2006, Iraqi Health Minister Ali al-Shamari estimated that approximately 100,000–150,000 Iraqi's had been violently killed since the start of the war. Ministry staff subsequently confirmed these figures.
Ministry totals are based on daily death counts reported at hospitals across the country and morgues in the Baghdad area, although no actual reports are published or publicly available. The Ministry began collecting mortality data in 2004, so the total estimate is based on currently reported daily death rates that have been extrapolated back to March 2003. The figures include all deaths (combat/non-combat) by violent causes. The reported daily death rate ranges from 75 to 100 per day, with a total of 100,000 to 150,000 estimated total deaths since the start of the war and a cause-specific MR due to violence of 1.01 to 1.34 per 1,000 per year.