Chapter 1: The Scope and Method of Economics

What is Economics?

Economics is the study of how individuals, firms, and societies make choices under conditions of scarcity. It focuses on the allocation of limited resources to satisfy unlimited wants.

• Scarcity: A good is scarce if its availability is limited in some way. Scarcity is not the same as poverty; poverty refers to an income level below which basic needs cannot be met.

• Microeconomics vs. Macroeconomics:

  • Microeconomics: Studies individual decision-making units, such as households, firms, and markets (e.g., price of gasoline, number of employees in an industry).

  • Macroeconomics: Examines the economy as a whole, including government policy and aggregate indicators (e.g., unemployment rate, inflation, GDP).

Five Foundations of Economics

1. Incentives: Motivations for people to act, which can be positive (rewards) or negative (penalties). Incentives often have unintended consequences. Example: Good grades as a positive incentive; expulsion for poor grades as a negative incentive.

2. Life is about Tradeoffs: Choosing one option means giving up others due to limited resources. Example: The cost of building a bomber could alternatively fund hospitals, power plants, or highways.

3. Opportunity Cost: The highest-valued alternative forgone when making a choice. Example: Waiting three weeks in line to save $300 on a TV; the opportunity cost is the best use of those three weeks.

4. Marginal Thinking: Evaluating whether the benefit of one more unit exceeds its cost. Example: Deciding to buy an additional textbook or use a coupon.

5. Trade: Specialization and exchange make all parties better off.

The Scientific Method in Economics

• Economists use the scientific method to construct and test models:

  1. Observe a phenomenon.

  2. Develop a hypothesis.

  3. Construct a model to test the hypothesis.

  4. Design experiments and collect data to verify, revise, or refute the hypothesis.

• Ceteris Paribus: Latin for "holding all else constant." Used to isolate the effect of one variable.

• Endogenous Variables: Variables controlled within the model.

• Exogenous Variables: Variables determined outside the model.

• Beware of Faulty Assumptions: Incorrect assumptions can lead to flawed conclusions (e.g., 2007 financial crisis and real estate prices).

Positive vs. Normative Analysis

• Positive Statements: Testable and verifiable (e.g., "The Nintendo Switch sold more consoles than the PlayStation 4").

• Normative Statements: Value judgments or opinions (e.g., "The Nintendo Switch has better games than other consoles").

Chapter 2: Scarcity and Choice

Opportunity Cost

The opportunity cost is the value of the next best alternative forgone to obtain something.

• Example: Traveling from Tucson to San Diego by bus ($100, 16 hours) or plane ($200, 6 hours). If you value your time at $8/hour:

  • Bus: $100 + 16 × $8 = $228

  • Plane: $200 + 6 × $8 = $248

  If you value your time at $C/hour, set costs equal: $100 + 16C = $200 + 6C → C = $10/hour.

• Example: Choosing between a Taylor Swift concert (value $150, ticket $99) and a free Justin Bieber concert. The opportunity cost of attending Bieber is $51 (the net value of Taylor Swift).

Production Possibility Frontier (PPF)

The PPF shows the maximum combinations of two goods that can be produced with fixed resources and technology.

• Points on the PPF represent efficient production; points inside are inefficient; points outside are unattainable.

• The PPF is typically bowed outward due to increasing opportunity costs.

• Example: A restaurant producing burgers and pizza; as more pizza is produced, the opportunity cost in terms of burgers increases.

• Investment in capital (factories, equipment) can shift the PPF outward over time.

Comparative and Absolute Advantage

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

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

• Specialization and trade based on comparative advantage allow all parties to benefit.

• Opportunity cost for Anna (per lawn): 4/3 dishes; for Beth: 2 dishes.

• Anna has a comparative advantage in mowing; Beth in dishes.

Chapter 3: Demand and Supply

Law of Demand

The law of demand states that, ceteris paribus, there is an inverse relationship between the price of a good and the quantity demanded.

• As price increases, quantity demanded decreases, and vice versa.

• Movement along the demand curve is a change in quantity demanded (due to price change).

• A shift of the demand curve is a change in demand (due to factors other than price, such as income, tastes, prices of related goods, expectations).

Law of Supply

The law of supply states that, ceteris paribus, there is a direct relationship between the price of a good and the quantity supplied.

• As price increases, quantity supplied increases.

• Movement along the supply curve is a change in quantity supplied (due to price change).

• A shift of the supply curve is a change in supply (due to input costs, technology, taxes/subsidies, expectations).

Market Equilibrium

Market equilibrium occurs where quantity demanded equals quantity supplied (Qd = Qs). The equilibrium price (P*) and quantity (Q*) are found by solving the equations for Qd and Qs.

• Example: Qd = 90 - 2P; Qs = -30 + P Set Qd = Qs: 90 - 2P = -30 + P → 120 = 3P → P* = 40 Q* = -30 + 40 = 10

Chapter 5: Elasticity

Price Elasticity of Demand

Price elasticity of demand measures the responsiveness of quantity demanded to a change in price.

• Formula:

• Elastic demand: |Ed| > 1 (quantity demanded is very responsive to price changes)

• Inelastic demand: 0 < |Ed| < 1 (quantity demanded is not very responsive)

• Unitary elasticity: |Ed| = 1

• Perfectly inelastic: Ed = 0; perfectly elastic: Ed approaches infinity

• Determinants: availability of substitutes, share of budget, time horizon

Calculating Elasticity

• Percentage method:

• Midpoint method:

Example: Tennis Passes in NYC

• Revenue increased for 1-Day passes, indicating inelastic demand.

• Elasticity calculation for 1-Day pass: (relatively inelastic)

Income Elasticity of Demand

• Measures how quantity demanded changes with income.

• Formula:

• Normal good: EI > 0; necessity: 0 < EI < 1; luxury: EI > 1; inferior good: EI < 0

Cross-Price Elasticity of Demand

• Measures how quantity demanded of one good responds to a price change in another good.

• Formula:

• EC > 0: substitutes; EC < 0: complements

• Example: If the price of chicken rises and people buy less rice, EC < 0; chicken and rice are complements.

Price Elasticity of Supply

• Measures how quantity supplied responds to price changes.

• Formula:

• Determined by time, flexibility, and adjustment process.

Chapter 4: Demand and Supply Applications

Consumer and Producer 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):

• Tax Revenue: Added to total surplus when a tax is imposed:

• Deadweight Loss (DWL): The loss in total surplus due to market distortions such as taxes.

Example Calculation

• Before tax: , ,

• After tax: , , ,

Chapter 19: Public Finance and Taxation

Taxes and Market Outcomes

• Per Unit Tax: A fixed tax on each unit sold.

• Levy: Who is legally responsible for paying the tax.

• Incidence: Who actually bears the economic burden of the tax (consumers and producers share the burden based on elasticity).

• Deadweight Loss: The reduction in economic activity and surplus due to the tax.

Tax Incidence Calculation

• Consumer share:

• Producer share:

• Example: If price rises from \frac{20-18}{5} \times 100 = 40\%

• The more inelastic side of the market bears a greater share of the tax burden.

Price Controls

• Price Ceiling: A legal maximum price. Binding if set below equilibrium, causing shortages and possibly black markets.

• Price Floor: A legal minimum price. Binding if set above equilibrium, causing surpluses (e.g., minimum wage leading to unemployment).

• Price Gouging: Raising prices during emergencies; often illegal and acts as a price ceiling.

Examples

• Rent control in Sweden: Long waitlists due to binding price ceilings.

• Minimum wage: If set above equilibrium wage, leads to unemployment and possible automation or relocation by firms.

• Zimbabwe hyperinflation: Price controls and excessive money printing led to economic collapse.

• Organ markets: Price ceiling of $0 for organs leads to black markets.

Summary Table: Effects of Market Interventions

Additional info: This guide covers foundational microeconomic concepts, including scarcity, opportunity cost, comparative advantage, market equilibrium, elasticity, and the effects of government intervention through taxes and price controls. These principles are essential for understanding how markets function and how policy can impact economic outcomes.