Cross-price elasticity is used to determine whether goods are inferior or normal goods.

Cross-Price Elasticity

A measure used in economics to show how the quantity demanded of one good changes in response to a change in the price of another good.

Inferior Goods

Goods for which demand decreases as the income of the consumer increases, opposite to normal goods.

Normal Goods

Goods for which demand increases as consumers' income increases, holding all other factors constant.