Macroeconomics Chapter 4: Demand and Supply
Demand and supply are the fundamental forces determining market prices and quantities, driven by consumer willingness to pay and producer willingness to sell.
Core Principles
- Law of Demand: As price increases, quantity demanded decreases, ceteris paribus.
- Law of Supply: As price increases, quantity supplied increases, ceteris paribus.
- Market Equilibrium: The point where quantity demanded equals quantity supplied, establishing the market price and quantity.
- Shifts vs. Movements: Changes in price cause movements along the curve, while changes in other factors shift the entire curve.
Action Steps
- 1. Identify the good or service being analyzed to define the market.
- 2. Determine the factors affecting demand (income, prices of related goods, tastes, expectations, number of buyers).
- 3. Determine the factors affecting supply (prices of inputs, technology, number of sellers, expectations, government policies).
- 4. Graph the demand and supply curves, plotting price on the vertical axis and quantity on the horizontal axis.
- 5. Find the intersection point to determine the equilibrium price and quantity.
- 6. Analyze shifts in demand or supply curves due to changes in non-price factors and determine the new equilibrium.
Formulas
- Demand Curve: $Q_d = f(P, Y, P_s, P_c, T, E)$
- Supply Curve: $Q_s = f(P, P_r, Tech, N, E)$
- Equilibrium: $Q_d = Q_s$
Key Terms
- Demand: The relationship between the price of a good or service and the quantity consumers are willing and able to purchase at various prices during a specific period.
- Supply: The relationship between the price of a good or service and the quantity producers are willing and able to sell at various prices during a specific period.
- Equilibrium Price: The price at which the quantity demanded equals the quantity supplied.
- Equilibrium Quantity: The quantity of a good or service bought and sold at the equilibrium price.
- Ceteris Paribus: A Latin phrase meaning 'all other things being equal,' used to isolate the effect of one variable on another.
Real World Examples
- A sudden increase in the price of gasoline.: This would cause a decrease in the quantity demanded for gasoline (movement along the demand curve) and potentially an increase in the demand for fuel-efficient cars (a shift in the demand curve for cars).
- A technological advancement that lowers the cost of producing smartphones.: This would lead to an increase in the supply of smartphones (a shift in the supply curve), resulting in a lower equilibrium price and a higher equilibrium quantity.
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