Commoly caused by an externality affecting the price of a good, such as a subsidy or tax, it exists when the equilibrium point is not optimal.
The "welfare triangle" region found when graphically representing monopolies is a specific form of this phenomenon. Joel Waldfogel argued that because a receiver of a gift usually makes a better decision when buying a gift than a giver, this quantity is present in Christmas shopping, while another example is a production shortfalls caused by erroneously small predictions of the amount of labor needed. Commoly caused by an externality affecting the price of a good, such as a subsidy or tax, it exists when the equilibrium point is not optimal. For 10 points, identify this economic phenomenon, a social cost caused by market inefficiency.
The "welfare triangle" region found when graphically representing monopolies is a specific form of this phenomenon.
{deadweight loss}