What is an Externality?

-Effect that Producers or Consumers of a Commodity has on People who have Naught to do with the Making or Consumption of the Good. They are called Third Parties -Can be Positive - External Benefits to Third Parties, or Negative - Externals Costs to a Third Party. -Can come from both Production [Making Steel can Harm the Environment] or Consumption [Someone Training to be a Doctor] [They are 'Consuming' the Training]