Supply and Demand
Supply and demand help explain how prices and quantities respond to shortages, changing preferences, and new production. Prices can also influence who receives a scarce good and whether producers invest in more capacity.
THE IDEA
Supply describes how much producers offer at different prices; demand describes how much buyers are willing and able to purchase. A change in either can alter the price and quantity traded. A shortage can put upward pressure on prices, while additional supply can put downward pressure on them.
Prices also affect allocation. When a scarce good is sold to the highest bidders, ability to pay influences who receives it. Market outcomes therefore do not simply measure how much people need something.
Higher expected profits can encourage investment, substitutes, or additional production. Low expected returns can discourage investment. These responses take time and depend on costs, financing, expectations, and the rules of the market.
When evaluating a price change, ask what changed in supply or demand, which constraints limit the response, and whether the change is likely to persist.
When to use it
As a consumer deciding between a scarce luxury item and a more available alternative
As a startup founder gauging market demand before scaling production
As an employee negotiating a raise in a tight labor market
As an investor recognizing overconfidence in a booming market
FROM THEORY TO EVERYDAY LIFE
In practice
Price Spike from Shortage
A failed harvest reduces the supply of a staple crop while demand remains high. Prices may rise, placing pressure on households with limited budgets and encouraging buyers to seek substitutes.
Investment Triggered by High Demand
A streaming service expects demand for original programs to increase and considers investing in production. It compares the expected subscription revenue with production costs and the risk that demand changes before the programs are released.
A MOMENT TO REFLECT
Put it to work.
How does your daily purchasing decision reflect the balance of supply and demand?
Which choices could you change in response to a higher price, and which purchases are difficult to substitute?
When have you experienced a sudden change in supply or demand that affected you personally?
CONTINUE THE CONVERSATION
Source texts
- The Great Mental Models Volume 4 Economics and Art