Basic Principles of Economics

Scarcity and Choice

Economics is the social science that studies how individuals, businesses, and governments make choices to cope with scarcity, the incentives that influence those choices, and the mechanisms that coordinate them.

• Scarcity: The universal condition that resources are limited while wants are unlimited.

• Incentives: Rewards or penalties ("carrots and sticks") that influence choices. For example, a price rise encourages sellers but discourages buyers.

• Coordination: The economy coordinates choices and allocates scarce resources to alternative uses.

• Types of Economies: Market economies (e.g., U.S.) use markets and prices; centrally planned economies (e.g., Cuba, North Korea) use government regulation.

Economics as a Social Science

• Uses the scientific method to understand and predict economic phenomena.

• Economic models: Simplified representations (often mathematical or graphical) of economic processes, e.g., the demand and supply model.

• Empirical methods include natural experiments, statistical investigations (correlation analysis), and laboratory experiments.

• Positive statements: Claims about what is, testable by facts.

• Normative statements: Claims about what should be, based on opinions or values.

Applications and Careers in Economics

• Economists work in academia, private firms (as data scientists, analysts), government, and international organizations.

• Key skills: Critical thinking, analytical ability, math, writing, and oral communication.

• Economics provides tools for personal, business, government, and community decision-making.

What, How, and For Whom: The Economic Problem

Goods and Services

• Goods: Tangible items (e.g., smartphones, pizza).

• Services: Intangible activities (e.g., haircuts, concerts).

• Resource allocation determines what and how much is produced.

• Production patterns vary by income level and change over time as economies develop.

Factors of Production

• Land: Natural resources (minerals, water, forests).

• Labor: Human effort, improved by human capital (skills, education).

• Capital: Tools, machines, buildings used in production.

• Entrepreneurship: Organizes other factors, innovates, and takes risks.

Changes in Production Methods

• Driven by education, training, technological advances, and artificial intelligence.

• Job creation and destruction occur as technology evolves.

• Global robot usage is increasing, but varies by country.

Income Distribution

• Income is earned from ownership of factors of production: rent (land), wages (labor), interest (capital), profit (entrepreneurship).

• Income inequality is measured by quintile shares; the highest quintile often earns a disproportionate share of total income.

Production Possibilities and Opportunity Cost

Production Possibilities Frontier (PPF)

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

• Attainable points: On or inside the PPF.

• Unattainable points: Outside the PPF.

• Efficient production: On the PPF (no resource waste).

• Inefficient production: Inside the PPF (resource waste).

Tradeoffs and Opportunity Cost

• Tradeoff: To produce more of one good, less of another must be produced.

• Opportunity cost: The value of the best alternative forgone.

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

Economic Growth

• Results from technological change and capital accumulation.

• Shifts the PPF outward, increasing future production possibilities.

• Involves a tradeoff: investing in capital goods reduces current consumption but increases future output.

Comparative and Absolute Advantage

• Comparative advantage: Ability to produce a good at a lower opportunity cost than others.

• Absolute advantage: Ability to produce more of a good with the same resources.

• Gains from trade arise from comparative, not absolute, advantage.

How Economic Life Is Organized

Households and Firms

• Households: Own factors of production and decide what to supply and consume.

• Firms: Hire factors of production and produce goods/services.

Markets and the Circular Flow

• Markets: Bring together buyers and sellers; can be for goods/services or factors of production.

• Market prices: Create incentives and coordinate decisions.

• Circular flow model: Visualizes the flow of resources, goods, services, and money between households and firms.

The Market Forces of Supply and Demand

Demand

• Quantity demanded: Amount buyers plan to purchase at a specific price and time.

• Law of demand: As price rises, quantity demanded falls (ceteris paribus).

• Substitution effect: Higher price leads consumers to substitute other goods.

• Income effect: Higher price reduces purchasing power.

• Demand schedule: Table of prices and quantities demanded.

• Demand curve: Graphical representation of the demand schedule.

• Market demand: Sum of all individual demands at each price.

Factors Shifting Demand

• Prices of related goods (substitutes and complements)

• Expected future prices

• Income (normal and inferior goods)

• Expected future income and borrowing

• Population

• Preferences

Supply

• Quantity supplied: Amount sellers plan to sell at a specific price and time.

• Law of supply: As price rises, quantity supplied rises (ceteris paribus).

• Supply schedule: Table of prices and quantities supplied.

• Supply curve: Graphical representation of the supply schedule.

• Market supply: Sum of all individual supplies at each price.

Factors Shifting Supply

• Prices of related goods (substitutes and complements in production)

• Resource prices

• Expected future prices

• Number of sellers

• Productivity (technology, natural events)

Market Equilibrium

• Equilibrium: Quantity demanded equals quantity supplied.

• Equilibrium price: Price at which market clears.

• Surplus: Quantity supplied exceeds quantity demanded; price falls.

• Shortage: Quantity demanded exceeds quantity supplied; price rises.

Predicting Changes in Price and Quantity

• Analyze whether an event affects demand, supply, or both.

• Determine direction of change (increase or decrease).

• Identify new equilibrium price and quantity.

Elasticity

Price Elasticity of Demand

• Measures responsiveness of quantity demanded to price changes.

• Formula:

• Elastic demand: Elasticity > 1

• Inelastic demand: Elasticity < 1

• Unit elastic: Elasticity = 1

• Perfectly elastic: Elasticity = ∞

• Perfectly inelastic: Elasticity = 0

Determinants of Elasticity

• Availability of substitutes

• Proportion of income spent on the good

• Time horizon

• Necessities vs. luxuries

Elasticity Along a Linear Demand Curve

• Elasticity varies along the curve: more elastic at high prices, more inelastic at low prices.

Total Revenue and Elasticity

• Total revenue:

• With elastic demand, price increase decreases total revenue.

• With inelastic demand, price increase increases total revenue.

Cross and Income Elasticity of Demand

• Cross elasticity:

• Positive for substitutes, negative for complements.

• Income elasticity:

• Positive for normal goods, negative for inferior goods.

Price Elasticity of Supply

• Measures responsiveness of quantity supplied to price changes.

• Formula:

• Elasticity depends on production and storage possibilities.

Consumer and Producer Surplus; Price Ceilings and Floors

Resource Allocation Methods

• Market price, command, majority rule, contest, first-come-first-served, sharing, lottery, personal characteristics, force.

Allocative Efficiency

• Achieved when resources produce the most highly valued goods/services.

• Occurs where marginal benefit (MB) = marginal cost (MC).

• Demand curve = MB curve; supply curve = MC curve.

Consumer Surplus

• Difference between what consumers are willing to pay (MB) and what they actually pay (market price).

• Graphically, area between demand curve and price, up to quantity bought.

Producer Surplus

• Difference between price received and marginal cost, summed over quantity produced.

• Graphically, area above supply curve and below price, up to quantity sold.

Market Efficiency and the Invisible Hand

• Competitive markets maximize total surplus (consumer + producer surplus).

• Adam Smith's "invisible hand": self-interested actions lead to efficient outcomes.

Market Failure

• Occurs when market equilibrium is not efficient (e.g., due to price/quantity regulations, taxes/subsidies, externalities, public goods, common resources, monopoly).

• Results in deadweight loss: reduction in total surplus.

Fairness in Markets

• Fair rules (Nozick): Voluntary exchange and property rights.

• Fair results (Rawls): Redistribution to maximize the share of the least well-off.

• Tradeoff between efficiency and equality.

Price Ceilings and Floors

• Price ceiling: Maximum legal price (e.g., rent control). Below equilibrium, causes shortages, illicit markets, discrimination, and deadweight loss.

• Price floor: Minimum legal price (e.g., minimum wage). Above equilibrium, causes surpluses (unemployment), illicit hiring, discrimination, and deadweight loss.

Introduction to Taxes and Subsidies

Tax Incidence

• Refers to how the burden of a tax is shared between buyers and sellers.

• Depends on the relative elasticities of demand and supply, not on whom the tax is legally imposed.

• With inelastic demand, buyers bear more of the tax; with inelastic supply, sellers bear more.

Types of Taxes

• Sales tax: Added to the price buyers pay.

• Excise tax: Subtracted from the price sellers receive.

• Both reduce equilibrium quantity and create a wedge between buyer and seller prices.

Elasticity and Tax Burden

• Perfectly inelastic demand: buyers pay all the tax.

• Perfectly elastic demand: sellers pay all the tax.

• Perfectly inelastic supply: sellers pay all the tax.

• Perfectly elastic supply: buyers pay all the tax.

Tax Efficiency and Deadweight Loss

• Efficient allocation: MB = MC, total surplus maximized.

• Taxes create deadweight loss (excess burden) unless demand or supply is perfectly inelastic.

• Deadweight loss increases with elasticity of demand or supply.

Fairness and Taxation

• Benefits principle: Taxes should reflect benefits received from public services.

• Ability-to-pay principle: Taxes should reflect the taxpayer's ability to pay.

• Horizontal equity: Equal ability to pay, equal taxes.

• Vertical equity: Greater ability to pay, higher taxes.

• Tax progressivity: Progressive (average tax rate rises with income), proportional (constant rate), regressive (average tax rate falls with income).

• Big tradeoff: Balancing fairness (equity) and efficiency in tax policy.

Summary Table: Types of Taxes and Their Progressivity

Examples and Applications

• Rent ceiling: New York City rent control benefits long-term residents but creates shortages for newcomers.

• Minimum wage: May increase unemployment among low-skilled workers, especially teenagers.

• Production quotas: Used in agriculture to raise prices, but cause underproduction and deadweight loss.

• Social Security tax: Burden falls mainly on workers due to inelastic labor supply.

Additional info: This guide covers foundational microeconomic concepts, models, and policy tools, with definitions, examples, and key formulas. For graphical analysis, refer to standard supply and demand, PPF, and surplus diagrams in your textbook.