Abstract
This study investigates the relationship between the strength of historic kin-based interaction networks in a region, and the strength of modern state capacity in that region. The author compares two metrics, across a global sample: firstly, the Kinship Intensity Index (KII), which is calculated by region using five variables from the Ethnographic Atlas (societies are combined by region by weighting each EA society using its population size); and secondly, the State Capacity Index (SCI), which measures the functionality of modern-day nation-states. It is found that around the world, countries whose borders have historically been home to societies with strong kin-based interaction networks tend to have a significantly weaker state capacity.