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Economics of Consumer Surplus

Jun 27, 2025

Overview

This lecture introduces the concepts of efficiency and economic surplus in the context of supply and demand, focusing specifically on consumer surplus.

Efficiency in Economics

  • Efficiency means maximizing the "pie" so no one can be helped without hurting someone else.
  • In markets, efficiency is achieved when all possible gains from trade are maximized.
  • Economists assess efficiency by determining if the market produces maximum happiness or benefit.

Economic Surplus

  • Economic surplus is a key tool to measure efficiency in supply and demand models.
  • There are two main types of surplus: consumer surplus and producer surplus (producer surplus will be covered in a later lecture).

Consumer Surplus

  • Consumer surplus is the extra benefit received when consumers pay less than what they are willing to pay for a good.
  • The demand curve shows consumers' willingness to pay at different prices.
  • Equilibrium price is where supply and demand intersect, setting the market price.
  • If someone is willing to pay $400 for a tablet but pays only $250 (the market price), their consumer surplus is $150.
  • Anyone buying the product values it at least as much as the price they pay, otherwise they wouldn't purchase it.
  • Consumer surplus varies by individual, depending on how much over the market price they value the product.
  • Graphically, consumer surplus is the area below the demand curve and above the market price, for all units sold.

Key Terms & Definitions

  • Efficiency — A market state where no one can be made better off without making someone else worse off.
  • Economic Surplus — The sum of benefits to all participants in a market.
  • Consumer Surplus — The difference between a consumer's willingness to pay and the actual price paid.

Action Items / Next Steps

  • Review notes on consumer surplus.
  • Await upcoming lecture or video on producer surplus.