Combining Supply and Demand Curves

Economic Concepts of Supply and Demand

Increase in Supply

• Key Concept: There is a clear relationship between price and quantity supplied.

  • At a given price, if marginal cost decreases (for instance), supply increases.

  • Example: If producing one unit incurs lower production costs (shift scenario), the quantity supplied of a good, like burgers, increases.

    • Depicted as a rightward shift in the supply curve.

Understanding Pricing and Demand

• Change in Price Context: If the price point rises from $15 to $18, demand is expected to increase, potentially leading to higher production.

• Supply Arising from Price Changes:

  • If only the price changes but costs remain the same, the supply will move along the curve, not shift.

• Key Distinction: Shifts vs. Movements

  • Shifts in supply curves occur due to changes other than price (e.g., production costs).

    • Example: If costs decrease (e.g., worker wages lower), the supply curve shifts to the right.

  • Movements occur when price is the only factor that changes while maintaining production costs.

Market Economy vs. Planned Economy

Planned Economy (Ex-USSR example)

• Definition: An economy where the government decides on production and distribution.

• Critique:

  • Costly and Inefficient: Hard to determine what needs production, who should produce, and who should consume.

  • Lack of Incentives: Without profit motives, there are fewer incentives for innovation or cost reduction.

  • Outcomes: Poor allocation of resources may happen due to bureaucratic inefficiencies.

Market Economy

• Adam Smith's Ideology: Free market mechanisms allow supply and demand to determine prices without major government intervention.

  • Belief in the 'invisible hand' of the market, suggesting that individual self-interests drive efficient outcomes.

• Flexibility of Markets:

  • Workers may find jobs that correspond to their skill levels, but income may not always meet living costs.

• Criticisms:

  • Markets can lead to income inequality and potentially ignore environmental consequences.

    • Example: Increased production may lead to pollution, as market forces alone do not ensure clean air or water.

Equilibrium in Market

• Definition: The point where quantity demanded equals quantity supplied, resulting in stable prices.

• Shifts in Demand and Supply:

  • When demand increases (demand curve shifts right), it typically results in higher prices and quantities supplied.

  • Conversely, an increase in supply (supply curve shifts right) leads to lower prices and higher quantities.

• Market Adjustments:

  • If the market price is above equilibrium, excess supply (surplus) occurs; producers will lower prices to encourage sales.

  • If the price is below equilibrium, excess demand (shortage) occurs; consumers will bid prices up, resulting in higher equilibrium prices.

Mathematical Representation of Demand and Supply

Demand Equation

• General Form: $Q_D = 57 - 7P$

  • Interpretation: For every $1 increase in price, quantity demanded decreases by 7.

Supply Equation

• General Form: $Q_S = 3 + 10P$

  • Interpretation: For every $1 increase in price, quantity supplied increases by 10.

Finding Equilibrium Price and Quantity

• Equilibrium Condition: $Q<em>D = Q</em>S$ implies $57 - 7P = 3 + 10P$

  • Rearranging gives: $17P = 54 <br>ightarrow P = rac{54}{17} <br>ightarrow P ext{ (approximately)} <br>ightarrow 3.18$

  • Substituting back yields the equilibrium quantity.

Identifying and Resolving Surplus and Shortage

Surplus

• Occurs when quantity supplied exceeds quantity demanded, prompting the market to lower prices.

Shortage

• Occurs when quantity demanded exceeds quantity supplied, prompting the market to raise prices.

Market Condition Examples

• Current market dynamics:

  • Shortage example: Lack of affordable housing while high market prices persist.

  • Surplus example: Excess amount of goods like clothes or food items leading to markdowns.

Revisiting Market Mechanics

• Effect of Demand Shift: An increase in consumer preference for a good will shift the demand curve to the right, leading to more quantity sought at every price.

• Effect of Supply Shift: A rise in raw material prices shifts the supply curve left, leading to a decrease in quantity supplied at existing prices.

Government Intervention Discussion

• Rationale for Intervention: In cases of significant market failure (like monopolies, public goods, etc.), government actions are necessary to stabilize markets.

• Examples of Government Intervention: Housing subsidies, regulations limiting price increases, and promoting competition to stabilize market conditions and ensure fair access.

Conclusion

• Understanding these economic principles equips students with tools to analyze real-world markets and predict outcomes based on varying demand or supply conditions.

• The balance between theoretical foundations, real-market implications, and the role of government is crucial in modern economic studies.