Core Economic Principles: Markets, Efficiency, and Strategy

Posted on Mar 13, 2026 in Economics

Fundamentals of Economics

Economics is the study of how agents allocate scarce resources and how those choices impact society. It relies on three pillars: Optimization (choosing the best feasible option), Empiricism (using data to test models), and Equilibrium (simultaneous optimization). It addresses complex human behavior, requiring adaptability and openness to new data.

Homo economicus: An idealized model of human behavior often contrasted with actual self-control issues (present bias) and bounded rationality found in behavioral game theory.

Opportunity Costs: The value of the best alternative use of resources. Continue consuming a good as long as the Marginal Benefit (MB) of the next unit is ≥ the Marginal Cost (MC).

Market Dynamics: Supply and Demand

Causes of Shifts:

  • Supply: Technology, number/scale of sellers, input costs, future expectations, and goals.
  • Demand: Tastes/preferences, income/wealth, number/scale of buyers, future expectations, and availability/price of related goods.

Movement along curves: Caused solely by changes in price.

Price Effects:

  • D Right / S Same: Price ↑, Quantity ↑
  • D Left / S Same: Price ↓, Quantity ↓
  • S Right / D Same: Price ↓, Quantity ↑
  • S Left / D Same: Price ↑, Quantity ↓
  • D Right / S Left: Price ↑, Quantity ambiguous
  • D Left / S Right: Price ↓, Quantity ambiguous

Curves:

  • Demand Curve: Represents Willingness to Pay (WTP) and Quantity Demanded (QD); downward sloping.
  • Supply Curve: Represents Willingness to Accept (WTA) and Quantity Supplied (QS); upward sloping.

Equilibrium and Efficiency

Equilibrium: Occurs where QS = QD and WTP ≥ WTA. Social surplus is not necessarily maximized, nor are Consumer Surplus (CS) or Producer Surplus (PS) guaranteed to be at their peak.

Price Controls:

  • Price Ceiling: Set below equilibrium; causes shortages (QS ≤ QD) and deadweight loss.
  • Price Floor: Set above equilibrium; causes surpluses (QS ≥ QD) and deadweight loss.

Social Surplus: Defined as WTP – WTA. It is maximized when MB = MC, ensuring the highest value buyers and lowest cost sellers participate. Note: Efficient allocation does not necessarily mean fair or equitable allocation.

Elasticity and Consumer Behavior

Elasticity Types:

  • Elastic: > 1
  • Unit Elastic: = 1
  • Inelastic: < 1
  • Perfectly Elastic: Horizontal graph; small price change leads to zero demand.
  • Perfectly Inelastic: Vertical graph; price changes do not affect demand.

Cross-Price & Income Elasticity:

  • Cross-Price: Complements have negative elasticity; substitutes have positive.
  • Income: Normal goods are directly related; inferior goods are inversely related. Luxury goods have an Income Elasticity (IE) ≥ 1.

Social Welfare and Policy

Frameworks:

  • Pareto Efficiency: No individual can be made better off without making someone else worse off.
  • Utilitarianism: Maximizes the sum of everyone’s utility.
  • Rawlsian: Maximizes the utility of the worst-off person.
  • Libertarian: Focuses on individualism, limited government, and process over redistribution.

Invisible Hand: The concept that self-interest, competition, and price signals ensure supply meets demand in a laissez-faire system. Market Failure (imperfect competition, externalities, or information asymmetry) may justify government intervention to improve social efficiency.

Game Theory and Trade

Strategic Analysis:

  • Nash Equilibrium: A situation where all players choose their best response simultaneously.
  • Dominant Strategy: A strategy that is optimal regardless of the opponent’s move.

Trade and Specialization:

  • Comparative Advantage: Producing at a lower opportunity cost than others.
  • Absolute Advantage: Producing more output with the same resources.
  • Trade: Allows agents to exceed their individual production possibilities, though it creates winners and losers.