
Why are some outputs or inputs that affect the level of
economic welfare not marketed?
The market is a vehicle for trade in commodities. For trade
to occur, property rights in the commodities have to be
reasonably complete and enforceable. Buyers may not be
willing to pay for an output or input unless they believe
they will have full and exclusive use of it for a specified
period of time, and will be able to sell it to someone else,
if they wish. Commodities that have these characteristics
are termed private goods.
Public goods are goods which lack some of the property
rights characteristics of private goods, and as a consequence
are not supplied in efficient levels by the private market.