Ethnic Groups' Access to State Power and Group Size

Ethnic-based political inequality is widespread, yet its underlying drivers remain poorly understood. This paper shows that an ethnic group's relative size is a key correlate of its access to central executive power. Using data on 575 groups across 181 countries from 1946 to 2021, I document a robust inverted-U-shaped relationship: groups of intermediate size are significantly more likely to gain political inclusion than both very small and very large ones. A simple model explains this pattern as the result of elite trade-offs between the risks of conflict from exclusion and the costs of sharing political rents. The model further predicts-and the data confirm-that the inverted-U is most pronounced in countries with historically competitive institutions. These findings offer new insight into the joint role of ethnic composition and institutions in shaping patterns of ethnic political inclusion.