Introduction to Economics

What is Economics?

Economics is the study of how individuals, firms, and societies allocate scarce resources to satisfy unlimited wants. It examines the choices made under conditions of scarcity and the consequences of those choices.

• Scarcity: The fundamental economic problem of having limited resources to meet unlimited wants.

• Choice: Because resources are scarce, choices must be made about how to use them.

Microeconomics vs. Macroeconomics

• Microeconomics: Focuses on the behavior of individual consumers, firms, and markets.

• Macroeconomics: Studies the economy as a whole, including issues like inflation, unemployment, and economic growth.

Positive vs. Normative Economics

• Positive Economics: Describes and explains economic phenomena; statements can be tested and validated ("what is").

• Normative Economics: Involves value judgments about what the economy should be like ("what ought to be").

• Example: "The unemployment rate is 5%" (positive); "The government should reduce unemployment" (normative).

Marginalism, Opportunity Cost, and Efficient Markets

• Marginalism: The analysis of the additional or incremental costs or benefits arising from a choice or decision.

• Opportunity Cost: The value of the next best alternative foregone when making a decision.

• Efficient Markets: Markets in which opportunities for profit are eliminated almost instantaneously.

Ceteris Paribus

• Ceteris Paribus: Latin for "all other things being equal"; used to isolate the effect of one variable by holding others constant.

Introductory Economic Models

Production Possibility Frontier (PPF)

The PPF is a curve showing the maximum attainable combinations of two goods that can be produced with available resources and technology.

• Endpoints: Represent the maximum output of one good if all resources are devoted to its production.

• Points Inside the PPF: Indicate inefficient use of resources.

• Points On the PPF: Indicate efficient production.

• Points Outside the PPF: Are unattainable with current resources.

• Shifts Outward: Caused by increases in resources or technological improvements.

• Shape: The PPF is typically bowed out (concave) due to the law of increasing opportunity cost.

Law of Increasing Opportunity Cost

• As production of one good increases, the opportunity cost of producing an additional unit rises.

Absolute and Comparative Advantage

• Absolute Advantage: The ability to produce more of a good with the same resources than another producer.

• Comparative Advantage: The ability to produce a good at a lower opportunity cost than another producer.

• Example: If Country A can produce either 10 cars or 5 trucks, and Country B can produce either 6 cars or 3 trucks, compare opportunity costs to determine comparative advantage.

Trade and Consumption Beyond Production

• Through specialization and trade, individuals and societies can consume beyond their own PPF.

Economic Systems: Command vs. Free Market

• Command Economy: The government makes all economic decisions.

• Free Market Economy: Decisions are made by individuals and firms interacting in markets.

Supply and Demand

Product and Resource Markets

• Product Markets: Where goods and services are bought and sold; households demand, firms supply.

• Resource Markets: Where resources (labor, capital) are bought and sold; firms demand, households supply.

Demand and Quantity Demanded

• Demand: The relationship between the price of a good and the quantity consumers are willing and able to buy at each price.

• Quantity Demanded: The specific amount consumers are willing to buy at a particular price.

• Law of Demand: As price falls, quantity demanded rises, ceteris paribus.

• Market Demand Curve: Found by horizontally summing individual demand curves.

Determinants of Demand

• Income/Wealth: Increases in income raise demand for normal goods, lower demand for inferior goods.

• Price of Substitutes: An increase raises demand for the good.

• Price of Complements: An increase lowers demand for the good.

• Other Determinants: Tastes, expectations, number of buyers.

Supply and Quantity Supplied

• Supply: The relationship between the price of a good and the quantity firms are willing and able to sell at each price.

• Quantity Supplied: The specific amount firms are willing to sell at a particular price.

• Law of Supply: As price rises, quantity supplied rises, ceteris paribus.

• Market Supply Curve: Found by horizontally summing individual supply curves.

Determinants of Supply

• Input Prices: Higher input prices decrease supply.

• Technology: Improvements increase supply.

• Other Determinants: Expectations, number of sellers, taxes/subsidies.

Market Equilibrium

• Equilibrium Price: The price at which quantity demanded equals quantity supplied.

• Above Equilibrium: Surplus; downward pressure on price.

• Below Equilibrium: Shortage; upward pressure on price.

• Shifting Curves: Changes in demand or supply shift the equilibrium price and quantity.

Consumer and Producer Surplus; Price Ceilings and Price Floors

Market Price and Rationing

• The market price allocates goods and services to those willing and able to pay.

Price Ceilings and Price Floors

• Price Ceiling: A legal maximum price; can cause shortages if set below equilibrium.

• Shortage: Quantity demanded exceeds quantity supplied at the ceiling price.

• Price Floor: A legal minimum price; can cause surpluses if set above equilibrium.

International Trade: Imports, World Price, and Tariffs

• World Price: The price of a good on the international market.

• Imports: Occur when the world price is below the domestic equilibrium price.

• Tariff: A tax on imports; raises domestic price, reduces imports.

Consumer Surplus, Producer Surplus, and Total Surplus

• Consumer Surplus (CS): The difference between what consumers are willing to pay and what they actually pay.

• Producer Surplus (PS): The difference between the price received and the minimum price at which producers are willing to sell.

• Total Surplus (TS): The sum of consumer and producer surplus; a measure of market efficiency.

• Graphical Representation: CS is the area below the demand curve and above the price; PS is the area above the supply curve and below the price.

Deadweight Loss

• Deadweight Loss: The reduction in total surplus that occurs when a market is not in equilibrium (e.g., due to price controls or taxes).

• Equilibrium Price: Minimizes deadweight loss by maximizing total surplus.

Elasticity

Elasticity: General Concept

• Elasticity measures the responsiveness of one variable to changes in another variable.

Price Elasticity of Demand

• Definition: The percentage change in quantity demanded divided by the percentage change in price.

• Formula:

• Interpretation: If , a 1% increase in price leads to a 1.5% decrease in quantity demanded.

• Calculation: Use the general formula between two points:

• Elastic:

• Inelastic:

• Unitary Elastic:

• Perfectly Elastic:

• Perfectly Inelastic:

Elasticity and Total Revenue

• Total Revenue (TR):

• Relationship: If demand is inelastic, an increase in price increases total revenue; if elastic, total revenue decreases.

Determinants of Price Elasticity of Demand

• Availability of substitutes

• Necessity vs. luxury

• Proportion of income spent on the good

• Time horizon

Cross-Price Elasticity of Demand

• Definition: Measures the responsiveness of demand for one good to changes in the price of another good.

• Formula:

• Interpretation: Positive sign indicates substitutes; negative sign indicates complements.

Income Elasticity of Demand

• Definition: Measures the responsiveness of demand to changes in income.

• Formula:

• Interpretation: Positive sign indicates a normal good; negative sign indicates an inferior good.

Price Elasticity of Supply

• Definition: Measures the responsiveness of quantity supplied to a change in price.

• Formula:

• Elastic Supply:

• Inelastic Supply:

• Perfectly Elastic Supply:

• Perfectly Inelastic Supply:

• Determinants: Flexibility of production, availability of inputs, time period considered.