UNIT 38 Substitute Goods

In economics, one way we classify goods (two or more) is by examining the relationship of the demand schedules when the price of one good changes. This relationship between demand schedules leads economists to classify goods as either substitutes or complements. Substitute goods are goods which, as a result of changed conditions, may replace each other in use (or consumption)[1]. A substitute good, in contrast to a complementary good, is a good with a positive cross elasticity of demand. This means a good's demand is increased when the price of another good is increased. Conversely, the demand for a good is decreased when the price of another good is decreased. If goods A and B are substitutes, an increase in the price of A will result in a leftward movement along the demand curve of A and cause the demand curve for B to shift out. A decrease in the price of A will result in a rightward movement along the demand curve of A and cause the demand curve for B to shift in.

Classic examples of substitute goods include margarine and butter, tea and coffee. Substitute goods not only occur on the consumer side of the market but also the producer side. Substitutable producer goods would include: petroleum and natural gas (used for heating or electricity). The degree to which a good has a perfect substitute depends on how specifically the good is defined. Take for example, the demand for Rice Krispies cereal, which is a very narrowly defined good as compared to the demand for cereal generally. The fact that one good is substitutable for another has immediate economic consequences: insofar (поскольку) 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.