Substitute good

In economics, one kind of good (or service) is said to be a substitute good for another kind insofar as the two kinds of goods can be consumed or used in place of one another in at least some of their possible uses. Classic examples of substitute goods include margarine and butter, or petroleum and natural gas (used for heating or electricity). The fact that one good is substitutable for another has immediate economic consequences: insofar as one good can be substituted for another, the demand for the two kinds of good will be bound together by the fact that customers can trade off one good for the other if it becomes advantageous to do so. Thus, an increase in price for one kind of good (ceteris paribus) will result in an increase in demand for its substitute goods, and a decrease in price (ceteris paribus, again) will result in a decrease in demand for its substitutes. Thus, economists can predict that a spike in the cost of wood will likely mean increased business for bricklayers, or that falling cellular phone rates will mean a fall-off in business for public pay phones.
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