Microeconomics Fundamentals: Key Concepts, Terms, and Applications

Definition of Economics

Scarcity and Choice

Economics is the social science that studies how people make choices to cope with scarcity, which arises because wants exceed the resources available to satisfy them. All economic questions stem from this fundamental problem.

• Scarcity: Limited resources versus unlimited wants.

• Microeconomics: The study of individual choices and markets.

• Macroeconomics: The study of the economy as a whole.

Example: Deciding how to allocate a limited budget between food and entertainment.

Two Big Economic Questions

What, How, and For Whom?

Economics addresses two central questions:

• What, how, and for whom are goods and services produced?

• Are choices made in pursuit of self-interest also promoting the social interest?

Example: Should a factory produce more electric cars or gasoline cars, and who benefits from this decision?

The Economic Way of Thinking

Tradeoffs and Marginal Analysis

Economists use a systematic approach to decision-making, focusing on tradeoffs and marginal analysis.

• Every choice involves a tradeoff—giving up one thing to get something else.

• People make rational choices by comparing benefits and costs.

• Opportunity cost: What you must give up to get something.

• Most choices are made at the margin by comparing marginal benefit and marginal cost.

Example: Deciding whether to study an extra hour or go out with friends.

Economics as Social Science and Policy Tool

Positive vs. Normative Statements

Economists distinguish between positive statements (what is) and normative statements (what ought to be). Economics is used to explain the world and to advise on policy decisions.

• Positive economics: Describes and explains economic phenomena.

• Normative economics: Prescribes what should be done.

Example: "Increasing the minimum wage will reduce poverty" (positive) vs. "The minimum wage should be increased" (normative).

Key Terms in Microeconomics

Essential Vocabulary

• Benefit: The gain or satisfaction received from a choice.

• Capital: Tools, equipment, and facilities used in production.

• Economic model: Simplified representation of economic processes.

• Efficient: Achieving maximum output with given resources.

• Entrepreneurship: The ability to organize resources and take risks.

• Factors of production: Land, labor, capital, entrepreneurship.

• Goods and services: Physical items and activities provided to satisfy wants.

• Human capital: Skills and knowledge of workers.

• Incentive: Reward or penalty that motivates behavior.

• Macroeconomics: Study of the economy as a whole.

• Microeconomics: Study of individual markets and choices.

• Marginal benefit: Additional benefit from one more unit.

• Marginal cost: Additional cost from one more unit.

• Opportunity cost: Value of the next best alternative forgone.

• Preferences: Individual tastes and priorities.

• Profit: Revenue minus cost.

• Rent: Payment for use of land or resources.

• Scarcity: Limited nature of resources.

• Self-interest: Pursuit of personal gain.

• Social interest: Outcomes beneficial to society as a whole.

• Tradeoff: Exchange of one benefit for another.

• Wages: Payment for labor.

Production Possibilities and Opportunity Cost

Production Possibilities Frontier (PPF)

The PPF shows the boundary between attainable and unattainable production levels when all resources are used efficiently.

• Points on the PPF: Efficient and attainable.

• Points inside the PPF: Attainable but inefficient.

• Points outside the PPF: Unattainable with current resources.

Opportunity cost is represented by the slope of the PPF.

Formula:

$\text{Opportunity Cost} = \frac{\text{Loss in Good Y}}{\text{Gain in Good X}}$

Example: Moving from one point to another on the PPF shows the tradeoff between producing cars and computers.

Using Resources Efficiently

Allocative and Productive Efficiency

Efficiency occurs when goods and services are produced at the lowest possible cost and in the quantities that bring the greatest possible benefit.

• Allocative efficiency: Producing the mix of goods most desired by society.

• Marginal benefit: Benefit from consuming one more unit.

• Marginal cost: Cost of producing one more unit.

• Resources are used efficiently when marginal benefit equals marginal cost.

Formula:

$\text{Efficient Allocation:} \quad MB = MC$

Gains from Trade

Comparative Advantage

Trade allows individuals and nations to specialize in activities where they have a comparative advantage, increasing overall efficiency and welfare.

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

• Specialization and trade lead to mutual gains.

Example: One country specializes in wheat, another in cars, and both trade for mutual benefit.

Economic Growth

Sources and Effects

Economic growth expands the PPF, allowing more goods and services to be produced.

• Growth results from capital accumulation and technological change.

• Growth increases future consumption possibilities.

Economic Coordination

Markets and Property Rights

Markets coordinate economic activity by matching buyers and sellers. Property rights and money facilitate efficient exchange.

• Markets work efficiently when property rights exist.

• Money makes trading more efficient.

Markets and Prices

Competitive Markets

A competitive market has many buyers and sellers, so no single buyer or seller can influence the price. Prices are determined by demand and supply.

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

• Demand and supply interact to determine prices.

Demand

Law of Demand

Demand is the relationship between the quantity demanded and the price, holding other influences constant.

• As price rises, quantity demanded falls (law of demand).

• Demand depends on prices of related goods, expected future prices, income, preferences, and population.

Formula:

$Q_d = f(P, P_r, Y, T, E)$

Where $Q_d$ is quantity demanded, $P$ is price, $P_r$ is price of related goods, $Y$ is income, $T$ is tastes/preferences, $E$ is expectations.

Supply

Law of Supply

Supply is the relationship between the quantity supplied and the price, holding other influences constant.

• As price rises, quantity supplied increases (law of supply).

• Supply depends on prices of inputs, technology, expected future prices, and number of sellers.

Formula:

$Q_s = f(P, P_i, T, E, N)$

Where $Q_s$ is quantity supplied, $P$ is price, $P_i$ is price of inputs, $T$ is technology, $E$ is expectations, $N$ is number of sellers.

Market Equilibrium

Equilibrium Price and Quantity

Market equilibrium occurs when quantity demanded equals quantity supplied.

• At equilibrium price, there is no shortage or surplus.

• Above equilibrium price: surplus; below equilibrium price: shortage.

Formula:

$Q_d = Q_s$

Predicting Changes in Price and Quantity

Shifts in Demand and Supply

Changes in demand or supply affect equilibrium price and quantity.

• Increase in demand: price rises, quantity rises.

• Decrease in demand: price falls, quantity falls.

• Increase in supply: price falls, quantity rises.

• Decrease in supply: price rises, quantity falls.

Price Elasticity of Demand

Responsiveness to Price Changes

Price elasticity of demand measures how much quantity demanded responds to a change in price.

• Formula:

$\text{Price Elasticity of Demand} = \frac{\% \text{ Change in Quantity Demanded}}{\% \text{ Change in Price}}$

• If demand is elastic, a price cut increases total revenue; if inelastic, a price cut decreases total revenue.

More Elasticities of Demand

Income and Cross Elasticity

Other elasticities measure responsiveness to changes in income and prices of related goods.

• Income elasticity of demand: $\frac{\% \text{ Change in Quantity Demanded}}{\% \text{ Change in Income}}$

• Cross elasticity of demand: $\frac{\% \text{ Change in Quantity Demanded of Good A}}{\% \text{ Change in Price of Good B}}$

• Positive cross elasticity: substitutes; negative: complements.

Elasticity of Supply

Responsiveness to Price Changes

Elasticity of supply measures how much quantity supplied responds to a change in price.

• Formula:

$\text{Elasticity of Supply} = \frac{\% \text{ Change in Quantity Supplied}}{\% \text{ Change in Price}}$

• Supply decisions have three time frames: momentary, short run, and long run.

Resource Allocation Methods

How Resources Are Allocated

Because resources are scarce, allocation methods include market price, command, majority rule, contest, first-come, first-served, lottery, and personal characteristics.

• Market price: resources go to those who pay the most.

• Command: resources allocated by authority.

• Lottery: random allocation.

Benefit, Cost, and Surplus

Consumer and Producer Surplus

Consumer surplus is the excess of the benefit received from a good over the amount paid. Producer surplus is the excess of the amount received over the cost of production.

• Marginal benefit curve: Shows maximum price willing to pay.

• Market supply curve: Horizontal sum of individual supply curves.

• Cost: What producers pay; price: What producers receive.

Is the Competitive Market Efficient?

Efficiency in Equilibrium

In competitive equilibrium, marginal social benefit equals marginal social cost, and resource allocation is efficient.

• Consumer and producer surplus are maximized.

• Producing less or more than the efficient quantity creates deadweight loss.

Is the Competitive Market Fair?

Fair Results and Fair Rules

Fairness can be defined as fair results (equal outcomes) or fair rules (equal opportunities).

• Fair results require income transfers from rich to poor.

• Fair rules require property rights and voluntary exchange.

Key Terms Table

Microeconomics Vocabulary

Term	Definition
Benefit	Gain or satisfaction from a choice
Capital	Tools and equipment used in production
Economic model	Simplified representation of economic processes
Efficient	Maximum output with given resources
Entrepreneurship	Ability to organize resources and take risks
Factors of production	Land, labor, capital, entrepreneurship
Goods and services	Physical items and activities provided
Human capital	Skills and knowledge of workers
Incentive	Reward or penalty motivating behavior
Macroeconomics	Study of the economy as a whole
Microeconomics	Study of individual markets and choices
Marginal benefit	Additional benefit from one more unit
Marginal cost	Additional cost from one more unit
Opportunity cost	Value of the next best alternative forgone
Preferences	Individual tastes and priorities
Profit	Revenue minus cost
Rent	Payment for use of land or resources
Scarcity	Limited nature of resources
Self-interest	Pursuit of personal gain
Social interest	Outcomes beneficial to society
Tradeoff	Exchange of one benefit for another
Wages	Payment for labor

Additional info: These notes expand on the original bullet points and chapter summaries, providing definitions, formulas, and examples for key microeconomics concepts. The structure follows a logical progression from foundational principles to market mechanisms and efficiency, suitable for college-level exam preparation.