Horizontal Economic Inequality and Mass Atrocity Risk: A Large-Sample Empirical Inquiry

Our research question is: Does inter-group horizontal economic inequality elevate state-perpetrated mass atrocity risk? Theoretical perspectives in genocide studies show how economic and other forms of discrimination against ethnic or religious groups can elevate the risk of government violence against them. Among the approximately five dozen large-sample empirical studies of mass atrocity risk, only a few consider the effects of economic discrimination. Moreover, no large-sample empirical studies, to the best of our knowledge, test hypotheses related to how inter-group horizontal economic inequalities (as distinct from vertical economic inequalities based on GINI coefficients or quantile income or wealth measures) affect mass atrocity risk. Drawing upon two data sources, we construct four horizontal economic inequality measures for groups within nations. The measures relate to access to economic resources in general and to electricity in particular. We then empirically test hypotheses related to horizontal economic inequality and mass atrocity risk for a sample of 175 nations spanning the period 1946–2019. We find modest support that horizontal economic inequality elevates mass atrocity risk broadly defined, but not genocide risk. We also find that vertical income inequality measures do not usually elevate mass atrocity or genocide risk.