Study Notes
Cross Elasticity of Demand (XED) measures how the quantity demanded of one good responds to a change in the price of another good. It helps understand the relationship between two goods.
- Cross Elasticity of Demand (XED) — the responsiveness of quantity demanded for one good to a change in the price of another good. Example: If the price of Pepsi increases, the demand for Coca-Cola may increase.
- Substitutes — goods with a positive XED, meaning the demand for one increases as the price of the other increases. Example: Pepsi and Coca-Cola.
- Complements — goods with a negative XED, meaning the demand for one decreases as the price of the other increases. Example: Coffee pods and coffee machines.
- Strong Substitutes — goods with a highly responsive demand to price changes of their substitutes. Example: Butter and margarine.
- Weak Substitutes — goods with a less responsive demand to price changes of their substitutes. Example: Bicycles and automobiles.
- Strong Complements — goods with a less responsive demand to price changes of their complements. Example: Software and computers.
- Weak Complements — goods with a highly responsive demand to price changes of their complements. Example: Tea and milk.
Exam Tips
Key Definitions to Remember
- Cross Elasticity of Demand (XED)
- Substitutes
- Complements
- Strong Substitutes
- Weak Substitutes
- Strong Complements
- Weak Complements
Common Confusions
- Confusing substitutes with complements
- Misunderstanding the direction of demand changes for substitutes and complements
Typical Exam Questions
- What is Cross Elasticity of Demand? It is the responsiveness of quantity demanded for one good to a change in the price of another good.
- Why do substitutes have a positive XED? Because the demand for one increases as the price of the other increases.
- Why do complements have a negative XED? Because the demand for one decreases as the price of the other increases.
What Examiners Usually Test
- Ability to calculate and interpret XED values
- Understanding the relationship between substitutes and complements
- Differentiating between strong and weak substitutes and complements