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M17.L05 — Market Failure and the Limits of the First Welfare Theorem

Module: Module 17 — Exchange Economy and General Equilibrium Lesson: L05 of 05 Duration: ~30 minutes Level: Intermediate Provenance: Principles of Microeconomics (Curtis and Irvine) | University of Utah Intermediate Microeconomics

Learning Objective

Identify situations where competitive markets fail to achieve Pareto efficiency.

When Markets Fail

The First Welfare Theorem's assumptions often fail in reality:

  1. Externalities: Unpriced side effects (e.g., Australia's coal seam gas water contamination)
  2. Social cost > private cost → overproduction

  3. Solution: Pigovian taxes (Australia's carbon pricing)

  4. Public Goods: Non-excludable, non-rival (e.g., national defense, clean air)

  5. Free rider problem → underprovision

  6. Australian example: Public broadcasting (ABC)

  7. Market Power: Monopolies distort prices (e.g., Australia's banking oligopoly)

  8. MR ≠ P → deadweight loss
  9. Remedy: ACCC regulation

Mathematically, externalities create divergence between private and social MRS.

Worked Example

[Australian context]

Coal power externality: 1. Private MC = $30/MWh 2. Social MC = $50/MWh (includes health costs) 3. Competitive equilibrium: Q_market where P = $30 4. Efficient quantity: Q* where P = $50 5. Deadweight loss = ∫_{Q*}^{Q_market} (50 - 30) dQ

Policy options: - Carbon tax of $20/MWh - Cap-and-trade (Australia's Safeguard Mechanism)

Common Misconception

"Government intervention always improves efficiency"

Correction: Government failure can worsen outcomes (e.g., Australia's home insulation program).

Key Takeaways

  • Market failures are pervasive in real economies
  • Australian policy provides concrete examples of each failure type
  • The Second Theorem suggests redistribution + markets can address equity
  • Policy design must account for potential government failures

Practice

  1. Calculate deadweight loss from a monopoly with given demand and cost curves
  2. Design a Pigovian tax for Australian agricultural runoff
  3. Compare Australia's NBN rollout with public goods theory predictions

Further Resources

Provenance: MIT OCW 14.01 Principles of Microeconomics | Intermediate Microeconomics with Excel (Barreto)