How a Market System Functions

Chapter 4 Goals

• Acquire a basic understanding of how free markets organize economic activity.

• Introduce markets and money into the Circular Flow Diagram.

• Develop and analyze the model of Supply and Demand.

• Appreciate the beneficial roles of profit and the entrepreneur in a market system.

Preliminary Circular Flow Diagram

• Households and Firms are the two primary economic decision-making institutions.

• In a mixed economy (and especially in more capitalist systems), much of the interaction between households and firms occurs in markets and is facilitated by money.

• The Preliminary Circular Flow Diagram illustrates the fundamental movement of resources between households and firms.

• When markets and money are added, flows include:

  • Consumption of Finished Goods and Services (Households -> Markets for Goods and Services; Household demand drives Firm revenues)

  • Output of Finished Goods and Services (Firms -> Markets for Goods and Services)

  • Use of Factors of Production (Households -> Markets for Factors of Production; Firms -> Markets for Factors of Production)

  • Payments of wages and rents (Firms pay Households for factors of production; Household incomes are wages/rents)

• This diagram captures the two sets of markets and the flow of resources, goods/services, and money.

Money

• Money is an asset socially and legally accepted as payment for goods/services.

• Three functions of money:

  • Medium of Exchange: used as payment when purchasing goods/services.

  • Store of Value: holds wealth over time.

  • Unit of Measure: a standard numerical unit of accounting (e.g., prices expressed in dollars).

• Example of price comparison facilitated by money: if a gallon of milk costs 2 and a gallon of gas costs 4, gas is twice as expensive as milk, i.e. rac{P{ ext{gas}}}{P{ ext{milk}}} = rac{4}{2} = 2.

Markets and Market Interactions

• Households and firms interact in two distinct sets of markets: 1) Markets for Finished Goods and Services

  • Where outputs from production are traded.

  • Firms are sellers; households are buyers.
    2) Markets for Factors of Production

  • Where inputs for production (labor, land, capital) are traded.

  • Households are sellers; firms are buyers.

• The interaction of these markets is shown by updating the Circular Flow Diagram to include:

  • Households supply factors of production to Firms

  • Firms provide wages and rents to Households as income

  • Households purchase Finished Goods and Services from Firms

  • Firms earn revenues from selling Finished Goods and Services

• This completes the Basic Circular Flow Diagram.

Model of Supply and Demand

• Purpose: explain how buyers and sellers interact in a free market and what price/quantity emerge.

• Equilibrium is the outcome where demand and supply interactions result in a stable price and quantity.

• Key questions:

  • What is the Quantity of Trade (how many units are traded)?

  • What is the Price (money exchanged per unit)?

• Demand and Supply summarize behavior:

  • Demand: relationship between the price of a good and the quantity that consumers are willing and able to purchase, all other factors fixed.

  • Supply: relationship between the price of a good and the quantity that firms are willing and able to sell, all other factors fixed.

• Graphical depiction:

  • Demand curve is typically drawn in blue (downward-sloping).

  • Supply curve is typically drawn in red (upward-sloping).

Demand and the Law of Demand; Supply and the Law of Supply

• Law of Demand: All else equal, a greater quantity of a good will be demanded at lower prices; demand curves slope downward.

• Law of Supply: All else equal, a greater quantity of a good will be supplied at higher prices; supply curves slope upward.

• Horizontal Interpretation: start at a price, move horizontally to read the corresponding quantity demanded/supplied.

• Vertical Interpretation: start at a quantity, move vertically to read the corresponding price.

Reservation Prices

• Buyer’s Reservation Price: the maximum amount a buyer is willing to pay for a given quantity demanded.

• Seller’s Reservation Price: the minimum amount a seller is willing to accept for a given quantity supplied.

• A reservation price is a cutoff price where buyer/seller behavior changes.

Equilibrium

• Equilibrium is a stable state for a market where price and quantity settle such that no individual buyer or seller can improve their surplus by changing behavior.

• Market Equilibrium is the point where Demand and Supply intersect and the resulting price/quantity is stable.

• Example scenario (illustrative, not the only case):

  • At a relatively high price such as p^* = 50, there may be excess supply (e.g., 75 units offered by sellers but only 15 buyers).

  • This creates downward pressure on price until the market clears.

• A specific equilibrium example given: p^* = 30,\ q^* = 55

  • At this price, quantity demanded equals quantity supplied; no excess demand or excess supply.

• Equilibrium properties:

  • Stable: the price tends to remain there unless outside factors change.

  • Unique: there is one equilibrium in a given demand/supply framework.

  • Self-enforcing: if price deviates, market forces push it back toward equilibrium (downward pressure when price is high; upward pressure when price is low).

• When demand or supply changes, the equilibrium price and quantity adjust accordingly.

Determinants of Demand and Supply (Underlying Determinants)

• These are factors other than the own price that influence decisions to purchase or sell.

• Changes in these factors cause shifts in the entire demand or supply curves, leading to new equilibrium prices/quantities.

• Two broad questions:

  • What are the determinants that shift demand? What about supply?

  • How do shifts differ from a change in own price (movement along the curve)?

Changes in Demand vs. Changes in Quantity Demanded

• A change in own price (the price of the good itself) changes the quantity demanded along a fixed demand curve (movement along the curve), not the relationship that defines demand.

• A change in any determinant other than own price changes the entire demand curve (a shift), altering the relationship between price and quantity demanded.

Determinants of Demand (Factors that Shift the Demand Curve)

• Increase in demand (rightward shift) occurs when consumers are more willing to purchase the good at every price:
  1) Decrease in the price of a Complement Good (e.g., buns for hotdogs get cheaper; hotdog demand rises)
  2) Increase in the price of a Substitute Good (e.g., Coke price goes up; demand for Pepsi rises)
  3) Increase in income (for Normal Goods)
  4) Decrease in income (for Inferior Goods)
  5) Increased consumer preferences for the good (e.g., health studies increasing demand for milk)
  6) Increase in market size (e.g., population growth)
  7) Expectation of higher future prices (e.g., expect gasoline to be more expensive tomorrow, so buy today)

• Opposite changes (decreases in demand) shift the demand curve leftward.

• Note: Changes in own price do not shift demand; they cause movement along the demand curve.

Determinants of Supply (Factors that Shift the Supply Curve)

• Increase in supply (rightward shift) occurs when firms are more willing to sell the good at every price:
  1) Decrease in the cost of factors of production (e.g., lower wages)
  2) Improvement in technology that reduces production costs
  3) Favorable realization of uncertain events (e.g., good weather for crops)
  4) Increase in market size (more suppliers)
  5) Expectation of lower future prices (e.g., yesterday’s high price suggests selling today before price falls)

• Decreases in supply shift the supply curve leftward.

• The own price of the good cannot change the position of the supply curve; it only changes the quantity supplied along the curve.

Interpreting Shifts: Horizontal vs. Vertical Interpretations

• Horizontal Interpretation (in terms of both demand and supply): increases/decreases are read as shifts to the right or left of the curves (increase = rightward shift; decrease = leftward shift).

• Vertical Interpretation (less common for everyday teaching): increases in demand are upward shifts for demand, but for supply, increases are downward shifts (and vice versa for decreases). This can be counterintuitive.

Shifts and Equilibrium

• When demand increases (D shifts right):

  • Equilibrium price rises, and equilibrium quantity rises.

• When demand decreases (D shifts left):

  • Equilibrium price falls, and equilibrium quantity falls.

• When supply increases (S shifts right):

  • Equilibrium price falls, and equilibrium quantity rises.

• When supply decreases (S shifts left):

  • Equilibrium price rises, and equilibrium quantity falls.

Role of Profit in a Market Economy

• Profits act as a signaling device that directs resources to their most valuable use.

• If firms in an industry earn large positive profits, this signals current firms to increase output or new firms to enter, attracting more resources to the market.

• If firms earn large negative profits, this signals current firms to reduce output or exit, diverting resources to more valued uses elsewhere.

• This signaling relies on freedom to engage in economic activity; resources must be allowed to pursue the highest return.

Role of the Entrepreneur

• Profits signaling works only if someone can recognize, appreciate, and respond to different profit levels: the Entrepreneur.

• An Entrepreneur undertakes and oversees business ventures, often with risk and initiative.

• The movement toward profit-driven reallocation of resources can involve bankruptcies of unprofitable firms.

• This concept ties to Joseph Schumpeter’s idea of capitalism as a “gale of creative destruction.”

Spontaneous Order in Markets

• Spontaneous order refers to natural, undirected emergence of order from individuals pursuing their own self-interest.

• In markets, this often yields outcomes better for society than deliberate central planning.

• Famous quotes/ideas:

  • Friedrich von Hayek argued markets allocate resources more efficiently than central designs.

  • Adam Smith’s Invisible Hand: individuals pursuing their own interests can collectively promote societal well-being more effectively than planned efforts.

• A practical illustration of spontaneous order is the pencil example, I, Pencil, by Leonard Read.

I, Pencil: A Tale of Market Coordination

• Core idea: No single person knows how to make a pencil from start to finish; production requires millions of people globally.

  • Components and inputs include: trees in California, loggers, sawmills, transport, workers’ meals, kiln drying, graphite from Sri Lanka, brass ferrule materials, clay from Mississippi, wax from Mexico, pumice from Italy, etc.

• The process involves inputs from diverse locations and competencies, coordinated without a central planner.

• The coordination occurs spontaneously through the price system and voluntary exchanges, not through a central directive.

• Key features highlighted in Read’s narrative:
  1) No single know-how to make a pencil;
  2) Most helpers do not intend to produce a pencil specifically;
  3) Yet the pencil is produced and valued through coordinated inputs.

• The market coordinates tiny, disjointed know-hows to meet societal needs without a master plan.

• In this system, prices convey information that leads to the appropriate allocation of resources and actions by individuals (entrepreneurs, workers, and consumers).

How Prices and Decisions Align (I Pencil implications)

• If society needs more pencils, demand for inputs (e.g., lumberjacks) increases; equilibrium price and quantity for pencils rise.

• The higher demand for inputs increases wages (e.g., lumberjack wages) to attract more workers.

• Individuals do not need to care about making a pencil per se; their pursuit of self-interest (earning wages, profits) aligns with societal needs through price signals.

Three Surprising Features of Market Coordination (from I Pencil)

• No single person possesses all the knowledge to make a pencil start-to-finish.

• Most who helped make the pencil do not intend to or necessarily care to make a pencil.

• Yet, the entire process happens without any planner and results in valued goods being produced.

Real-World Relevance and Implications

• The market system coordinates complex, dispersed knowledge efficiently through price signals.

• The concept of spontaneous order supports arguments for limited government intervention and for allowing entrepreneurial activity and competitive markets to allocate resources.

• Understanding the distinction between changes in demand/supply and changes in the own price is crucial for predicting how equilibrium prices and quantities move.

• The chain of thought underpinning profit as a signaling device emphasizes the importance of entry, competition, and the potential consequences of restrictions on bankruptcy or firm exit.

ext{Equilibrium condition:}
Q^D(p^) = Q^S(p^) \ p^: ext{ equilibrium price},\, q^: ext{ equilibrium quantity},

• Example: p^* = 30,\, q^* = 55 where the quantity demanded equals the quantity supplied.

• If preferences, incomes, technology, or other determinants shift the curves, new equilibrium values arise according to the direction of the shift.

• Price signal mechanisms and the tendency toward self-enforcement underlie the stability and efficiency of markets, according to the classical and Austrian perspectives discussed (including Hayek and Smith).