What Is Supply And Demand?

Definition

Supply and demand refers to the fundamental economic model that determines prices and quantities of goods and services in a market, first described by Adam Smith in 1776.

How It Works

The supply and demand model operates through the interaction of two primary forces: the supply curve, which represents the quantity of a good or service that producers are willing to sell at a given price, and the demand curve, which represents the quantity that consumers are willing to buy at that price. According to Ricardo's comparative advantage model, 1817, countries should specialize in producing goods for which they have a lower opportunity cost, leading to more efficient production and trade. The point at which the supply and demand curves intersect is known as the market equilibrium, where the quantity supplied equals the quantity demanded. For instance, Boeing produces ~800 aircraft annually (Boeing annual report), and the demand for these aircraft is influenced by factors such as airline industry growth and government regulations.

The supply curve is influenced by factors such as production costs, technology, and expectations of future prices. For example, if the cost of labor or raw materials increases, the supply curve will shift to the left, indicating that producers are willing to supply fewer goods at each price level. On the other hand, the demand curve is influenced by factors such as consumer preferences, income, and prices of related goods. According to Marshall's supply and demand framework, 1890, the demand curve is more elastic in the long run, meaning that consumers are more responsive to price changes over time. The demand for aircraft, for instance, is influenced by the price of fuel, with higher fuel prices leading to increased demand for more fuel-efficient aircraft.

The supply and demand model can be applied to different markets, including labor markets. In the labor market, the supply of labor is influenced by factors such as wages, working conditions, and education levels, while the demand for labor is influenced by factors such as technological change and economic growth. For example, the Solow growth model, 1956, explains how technological progress can lead to increased productivity and economic growth, which in turn can lead to increased demand for labor. The supply and demand model can also be used to analyze the impact of government policies, such as taxes and subsidies, on different markets.

Key Components

• Price elasticity of demand: measures how responsive the quantity demanded is to changes in price, with a higher elasticity indicating a greater response. An increase in price elasticity of demand leads to a decrease in the quantity demanded, while a decrease in price elasticity of demand leads to an increase in the quantity demanded.
• Supply chain: refers to the network of organizations and activities involved in producing and delivering a product, from raw materials to end consumers. An increase in supply chain efficiency leads to a decrease in production costs, while a decrease in supply chain efficiency leads to an increase in production costs.
• Opportunity cost: represents the value of the next best alternative that is given up when a choice is made, such as the opportunity cost of using labor to produce one good instead of another. An increase in opportunity cost leads to a decrease in the quantity supplied, while a decrease in opportunity cost leads to an increase in the quantity supplied.
• Substitutes: are goods or services that can be used in place of each other, such as coffee and tea, and an increase in the price of one substitute leads to an increase in demand for the other.
• Complements: are goods or services that are used together, such as cars and gasoline, and an increase in the price of one complement leads to a decrease in demand for the other.
• Market structure: refers to the characteristics of a market, such as the number of firms, the level of competition, and the degree of product differentiation, which can influence the supply and demand curves. An increase in market competition leads to a decrease in prices, while a decrease in market competition leads to an increase in prices.

Common Misconceptions

Myth: The supply and demand model only applies to perfectly competitive markets — Fact: The supply and demand model can be applied to different market structures, including monopolies and oligopolies, as explained by Cournot's oligopoly model, 1838.

Myth: The supply curve is always upward-sloping — Fact: The supply curve can be downward-sloping in certain cases, such as when a decrease in price leads to an increase in supply due to a reduction in production costs.

Myth: The demand curve is always downward-sloping — Fact: The demand curve can be upward-sloping in certain cases, such as when a higher price leads to an increase in demand due to a prestige effect.

Myth: The supply and demand model is only used in microeconomics — Fact: The supply and demand model can be used in macroeconomics to analyze the impact of government policies on the overall economy, as explained by Keynes' general theory, 1936.

In Practice

The supply and demand model can be applied to the aircraft industry, where Boeing and Airbus are the two main competitors. In 2019, Boeing produced 380 commercial aircraft (Boeing annual report), while Airbus produced 863 commercial aircraft (Airbus annual report). The demand for aircraft is influenced by factors such as airline industry growth, government regulations, and fuel prices. For instance, the increase in fuel prices in 2020 led to an increase in demand for more fuel-efficient aircraft, such as the Airbus A320neo and the Boeing 737 MAX. The supply of aircraft is influenced by factors such as production costs, technology, and expectations of future prices. The interaction between the supply and demand curves in the aircraft industry determines the prices and quantities of aircraft, with the market equilibrium representing the point at which the quantity supplied equals the quantity demanded.