WikiLeaks and Iraq body count: The sum of parts may not add up to the whole-a comparison of two tallies of Iraqi civilian deaths

Introduction The number of civilians killed in Iraq following the 2003 invasion has proven difficult to measure and contentious in recent years. The release of the Wikileaks War Logs (WL) has created the potential to conduct a sensitivity analysis of the commonly-cited Iraq Body Count's (IBC's) tally, which is based on press, government, and other public sources. Hypothesis The 66,000 deaths reported in the Wikileaks War Logs are mostly the same events as those previously reported in the press and elsewhere as tallied by iraqbodycount.org. Methods A systematic random sample of 2500 violent fatal War Log incidents was selected and evaluated to determine whether these incidents were also found in IBC's press-based listing. Each selected event was ranked on a scale of 0 (no match present) to 3 (almost certainly matched) with regard to the likelihood it was listed in the IBC database. Results Of the two thousand four hundred and nine War Log records, 488 (23.8%) were found to have likely matches in IBC records. Events that killed more people were far more likely to appear in both datasets, with 94.1% of events in which ≥20 people were killed being likely matches, as compared with 17.4% of singleton killings. Because of this skew towards the recording of large events in both datasets, it is estimated that 2035 (46.3%) of the 4394 deaths reported in the Wikileaks War Logs had been previously reported in IBC. Conclusions Passive surveillance systems, widely seen as incomplete, may also be selective in the types of events detected in times of armed conflict. Bombings and other events during which many people are killed, and events in less violent areas, appear to be detected far more often, creating a skewed image of the mortality profile in Iraq. Members of the press and researchers should be hesitant to draw conclusions about the nature or extent of violence from passive surveillance systems of low or unknown sensitivity.