Externality A consequence of an economic activity that is experienced by unrelated third parties. An externality can be either positive or negative. Investopedia Says: Pollution emitted by a factory that spoils the surrounding environment and affects the health of nearby residents is an example of a negative externality. An example of a positive externality is the effect of a well-educated labor force on the productivity of a company. Related Terms: Economics Impact Fee Land Rehabilitation Macroeconomics Marginal Social Cost - MSC Microeconomics Pigovian Tax Social Good True Cost Economics |