Supply and Demand

Notes on Supply and Demand

  • Supply: The total amount of a good or service available for purchase at any given price. Typically, as the price increases, the quantity supplied also increases, creating a positive relationship.

  • Demand: The desire for a good or service combined with the ability to purchase it. Generally, as the price decreases, the quantity demanded increases, resulting in a negative relationship.

  • Law of Demand: States that all else being equal, an increase in price results in a decrease in the quantity demanded.

  • Law of Supply: Indicates that all else being equal, an increase in price results in an increase in the quantity supplied.

  • Equilibrium: The point at which the quantity of goods supplied is equal to the quantity of goods demanded. At this point, market forces are balanced and prices tend to stabilize.

  • Shifts in Curves:

    • Demand Shift: Factors like consumer preferences, income levels, and prices of related goods can cause demand to shift left (decrease) or right (increase).

    • Supply Shift: Changes in production costs, technology, or the number of suppliers can lead to a leftward (decrease) or rightward (increase) shift in supply.

  • Elasticity: Describes how much the quantity demanded or supplied responds to changes in price.

    • Price Elasticity of Demand: Measures how the quantity demanded changes in response to a price change.

      • Elastic Demand: If the price elasticity is greater than 1, a small change in price leads to a large change in quantity demanded. Luxury goods often show elastic demand as consumers can forgo these goods when prices rise.

      • Inelastic Demand: If the price elasticity is less than 1, a change in price has little effect on the quantity demanded. Necessities like insulin or gasoline typically have inelastic demand since consumers will buy them regardless of price changes.

    • Price Elasticity of Supply: Measures how the quantity supplied changes in response to a price change.

      • Elastic Supply: An elasticity greater than 1 indicates that producers can easily increase production when prices rise, often seen in industries with readily available resources.

      • Inelastic Supply: An elasticity less than 1 suggests that producers cannot significantly change output in response to price changes, often due to long production times or limited resources.

    • Factors Influencing Elasticity:

      • Substitutes: The availability of substitutes makes demand more elastic; consumers can switch products if prices rise.

      • Time Frame: Demand elasticity can vary over time; it may be more elastic in the long run as consumers adjust their behavior.

      • Proportion of Income: Goods that take up a larger proportion of a consumer’s income tend to have more elastic demand because price changes significantly impact purchasing decisions.