Elasticity: A measure of how one variable responds to changes in another.
Price Elasticity of Demand (PED): Responsiveness of quantity demanded to price changes.
Elastic Demand: PED > 1; quantity demanded changes significantly with price.
Inelastic Demand: PED < 1; quantity demanded changes minimally with price.
Unit-Elastic Demand: PED = 1; quantity demanded changes proportionally with price.
Midpoint Formula: A consistent method for calculating elasticity across ranges.
Cross-Price Elasticity: Measures how demand for one good changes with price changes of another (substitutes or complements).
Income Elasticity of Demand: Reflects demand changes in response to income variations (normal vs. inferior goods).
Price Elasticity of Supply (PES): Responsiveness of quantity supplied to price changes.
Total Revenue: Total sales revenue affected by price elasticity.
Externalities: Costs or benefits affecting third parties outside a transaction (e.g., pollution, education).
Market Failure: Inefficient allocation of resources due to unaccounted externalities.
Private Marginal Costs/Benefits: Direct costs or benefits for individuals or firms in a transaction.
Social Marginal Costs/Benefits: Total costs/benefits, including external effects.
Public Goods: Goods that are nonrival (use by one doesn’t reduce availability) and nonexcludable (cannot exclude others).
Free-Rider Problem: Under-provision of public goods due to individuals benefiting without contributing.
Property Rights: Legal rights to resource use, essential for managing resources efficiently.
Coase Theorem: States that with low transaction costs and clear property rights, externalities can be resolved through negotiation.
Elasticity measures how changes in one variable (e.g., price) affect another (e.g., demand or supply).
Key to understanding consumer behavior, producer strategies, and market dynamics.
Formula: PED=%Change in Quantity Demanded%Change in Price\text{PED} = \frac{\% \text{Change in Quantity Demanded}}{\% \text{Change in Price}}PED=%Change in Price%Change in Quantity Demanded
Always negative (inverse relationship between price and demand), but absolute values are used for comparison.
Elastic Demand (PED > 1): Significant response in demand to price changes.
Inelastic Demand (PED < 1): Minimal response in demand to price changes.
Unit-Elastic Demand (PED = 1): Proportional response in demand to price changes.
Ensures consistent results: PED=(Q2−Q1)/[(Q2+Q1)/2](P2−P1)/[(P2+P1)/2]\text{PED} = \frac{(Q_2 - Q_1) / [(Q_2 + Q_1)/2]}{(P_2 - P_1) / [(P_2 + P_1)/2]}PED=(P2−P1)/[(P2+P1)/2](Q2−Q1)/[(Q2+Q1)/2]
Substitutes: Positive elasticity (e.g., Coke and Pepsi).
Complements: Negative elasticity (e.g., coffee and sugar).
Normal Goods: Positive elasticity (demand increases with income).
Inferior Goods: Negative elasticity (demand decreases with income).
Reflects responsiveness of quantity supplied to price changes.
Formula: PES=%Change in Quantity Supplied%Change in Price\text{PES} = \frac{\% \text{Change in Quantity Supplied}}{\% \text{Change in Price}}PES=%Change in Price%Change in Quantity Supplied
Demand Elasticity:
Availability of substitutes.
Necessity vs. luxury.
Proportion of income spent.
Time horizon.
Supply Elasticity:
Production flexibility.
Availability of inputs.
Time to adjust production.
Elastic Demand: Price increase → Decrease in total revenue.
Inelastic Demand: Price increase → Increase in total revenue.
Unit-Elastic Demand: Price changes → No change in total revenue.
Negative Externalities: Costs imposed on others (e.g., pollution).
Positive Externalities: Benefits enjoyed by others (e.g., education).
Occurs when externalities prevent efficient market outcomes.
Often requires policy interventions (e.g., taxes, subsidies).
Private Marginal Costs/Benefits: Direct costs or benefits for transaction participants.
Social Marginal Costs/Benefits: Includes external effects on third parties.
Characteristics of Public Goods:
Nonrivalry: One person’s use doesn’t reduce availability.
Nonexcludability: Cannot exclude others from using the good.
Free-Rider Problem: Under-provision when individuals benefit without paying.
Clear property rights ensure efficient resource allocation.
Lack of property rights leads to overuse or resource depletion.
Principle: Clear property rights + Low transaction costs → Negotiated solutions to externalities.
Limitations: High transaction costs or unclear property rights hinder applicability.