The efficiency loss of a tax is the tax revenue collected by government minus the value of the public goods financed through the tax.

Efficiency Loss

The decrease in economic efficiency that occurs when a market outcome does not allocate resources in the most economically beneficial way, often due to externalities or market failures.

Public Goods

Goods that are non-excludable and non-rivalrous, meaning they can be used by everyone and one person’s use does not diminish another's.