Answer to Question #45809 in Microeconomics for Debanjan Raul

Question

what is the difference between cross price elasticity of demand and income elasticity of demand?

Answer 1

Cross price elasticity of demand measures how much demand of one good, say x changes when the price of another good, say y changes, holding everything else constant. For example, you can measure what happens to the demand of bread when the price of milk changes. The cross price elasticity is calculated as the percentage change in the quantity demanded of good x divided by the percentage change in the price of good y. If the cross price elasticity is negative, then we call such goods Complements (example: pizza and soft drinks -- they are consumed together). If the cross price elasticity is positive, then we call such goods Substitutes (example: pizza and burgers -- you usually consume either or). The income elasticity of demand measures the change in the quantity demanded of some good, when the income changes, holding everything else constant. For example you can measure what happens to the demand for expensive red wine when income increases. The income elasticity is calculated as the percentage change in the quantity demanded of the good divided by the percentage change in income. If the income elasticity for a good is positive we call them normal goods. It can be between 0 and 1, and we call it income inelastic demand for goods such as food, clothing, newspaper. If it is above 1, we call it income elastic demand. Examples are the red wine, cruises, jewelry, art, etc. If the income elasticity is negative, this means that as income increases, the quantity demanded for those goods actually decreases, we call those goods inferior goods. Examples are "Ramen noodles", cheap red wine, potatoes, rice. etc.