ABSTRACT
In traditional or tribal societies, private property rights over resources are rare. Resources important to the life of the tribe are either held in common (like a common grazing ground) or are not owned at all (like animals that are hunted for food). A resource that is available to everyone (nonexcludable), but use of the resource may diminish the quantity or quality available to others (rival). A classic example of a common property resource is an ocean fishery. The tendency for common property resources to be overexploited because no one has an incentive to conserve the resource while individual financial incentives promote expanded exploitation. Economists seeking to determine efficient outcomes focus on comparing marginal benefits and marginal costs. Iceland has one of the most extensive systems of individual transferable quotas for its marine fisheries. The need for social regulation to manage common-property resources has been well recognized throughout history.
