Researchers challenge widely-cited Lancet Gaza mortality survey

New research is challenging the findings of a "Lancet Global Health" controversial Gaza Mortality Survey, arguing that the study relied on a flawed sample that may have significantly inflated estimates of war-related deaths in Gaza.

The new analysis was conducted by Professor Emeritus Sergio DellaPergola of the Hebrew University of Jerusalem and independent researcher Mark Zlochin.

The Lancet survey has been widely cited by critics of Israel in debates over civilian casualties in Gaza and allegations of Israeli "war crimes" and "genocide."

The British medical journal reported that some 75,200 people had died in Gaza since the start of the war, which began after the Oct. 7, 2023, Hamas massacre in southern Israel that killed approximately 1,200 people and saw 251 individuals kidnapped from Israeli border communities.

However, the report argues that the Lancet survey used an inaccurate sample of the population in Gaza. The researchers noted that the Gaza9 and Gaza3 interviewer teams were statistical outliers that “diverge materially from those of the remaining teams.”

Furthermore, DellaPergola and Zlochin found that roughly one-quarter of the reported violent deaths in Gaza were claimed by only 8% of the total survey sample.

“Population-level mortality estimates are only as reliable as the representativeness of the underlying sample,” DellaPergola explained. “Our analysis raises important questions regarding whether the survey achieved the level of representativeness necessary to support its national mortality estimates.”

The researchers also identified additional anomalies in the survey. They noted that survey teams focused only on small portions of the areas they were assigned to cover and pointed to discrepancies in the estimated number of Gaza prisoners.

Israel has strongly rejected allegations that it has deliberately targeted civilians, emphasizing that the Israeli military seeks to minimize civilian casualties while Hamas terrorists deliberately use Gazan civilians as human shields, a war crime under international law.

The Lancet has faced criticism from pro-Israel observers in the past. Earlier this month, the medical journal published a petition urging the World Medical Association (WMA) to suspend the Israel Medical Association.

The petition, which was created by the People’s Health Movement (PHM), Artsen voor Gaza (Doctors for Gaza), and the Health Advisory Council of Jewish Voice for Peace, argued that the Israeli medical organization should be expelled due to “its failure to speak out against the genocide of Palestinians, the destruction of health-care infrastructure, and the torture and killing of health-care workers in Gaza.”

In July 2024, the Lancet published a correspondence by doctors Rasha Khatib, Martin McKee, and Salim Yusuf, stating that “it is not implausible to estimate that up to 186,000 or even more deaths could be attributable to the current conflict in Gaza.”

The piece was published as a correspondence rather than a peer-reviewed academic article. Nevertheless, it was widely cited by anti-Israel activists and public figures, including UN Special Rapporteur Francesca Albanese.

Even the Hamas-run Gaza Health Ministry has not claimed casualty figures as high as those suggested in the study.

In September 2024, a professor at the Wharton Department of Statistics and Data Science stated that the Hamas-controlled Gaza Health Ministry exaggerates and distorts Gaza casualty figures.