Between-group contests over group-specific public goods with within-group fragmentation

We model a contest between two groups of equal population size over the division of a group-specific public good. Each group is fragmented into sub-groups. Each sub-group allocates effort between production and contestation. There is perfect coordination within sub-groups, but sub-groups cannot coordinate with one another. All sub-groups choose effort allocations simultaneously. We find that aggregate rent-seeking rises, social welfare falls, and both communities are worse off when the dominant sub-groups within both communities increase their population shares relative to the respective average sub-group population. Any unilateral increase in fragmentation within a group reduces conflict and makes its opponent better off. The fragmenting community itself may however be better off as well, even though its share of the public good falls. Thus, a reduced share of public good provisioning cannot be used to infer a negative welfare implication for the losing community.