Accounting for uncertainty in conflict mortality estimation: an application to the Gaza War in 2023-2024.

The ongoing Gaza War has resulted in significant loss of life and intensified an existing humanitarian crisis. Despite increasing demand for accurate data, mortality estimates remain challenging due to the inherent 'statistical fog of war'. Accurate quantification is hindered by incomplete reporting and uncertain age-sex distributions of casualties. Official death tolls are likely influenced by damaged infrastructure, security disruptions, and political motivations, complicating detailed demographic verification. Our study introduces a novel methodological approach-a Bayesian model incorporating novel priors-to explicitly account for measurement errors in mortality estimation by addressing reporting completeness and uncertainty in demographic distributions. We use these methods to estimate sex- and age-specific mortality patterns and associated life expectancy (LE) and LE losses due to direct conflict deaths from the Gaza War. We find that LE in Gaza was 42.3 (39.4-45.0) in 2023 and 40.4 (37.5-43.0) in 2024, corresponding to LE losses of 34.4 (31.7-37.3) and 36.4 (33.8-39.3) years, respectively, compared to a counterfactual scenario with no conflict-related deaths. This corresponds to 78,318 (70,614-87,504) conflict deaths by the end of 2024, reflecting a 14-fold increase in all-cause mortality during the conflict's first year. The age-sex pattern of Gaza's conflict deaths aligns with UN-IGME profiles from past genocides. To contextualize these estimates, we compare them with LE losses observed in the Gaza Strip, the West Bank, and all of Palestine between 2012 and 2019. Our estimates align with previously published work, after adjusting the reporting priors to ignore underreporting. Our versatile and robust framework for mortality estimation under conditions of data scarcity can inform future conflict research.