Glossary term
Elasticity
Elasticity measures how responsive one variable is to a change in another variable, such as demand responding to price.
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What Is Elasticity?
Elasticity measures how responsive one variable is to a change in another variable. In economics, it is often used to describe how quantity demanded or supplied changes when price, income, or another factor changes.
The most common example is price elasticity of demand. It asks how much the quantity demanded of a good changes when its price changes.
Key Takeaways
- Elasticity measures responsiveness.
- Price elasticity of demand compares quantity demanded with price changes.
- Elastic demand means quantity changes by a larger percentage than price.
- Inelastic demand means quantity changes by a smaller percentage than price.
- Elasticity helps explain pricing, tax effects, revenue, and consumer behavior.
Elasticity Formula
For price elasticity of demand, the numerator is the percentage change in quantity demanded. The denominator is the percentage change in price. Economists often use absolute values when discussing whether demand is elastic or inelastic.
Elasticity is usually expressed as a ratio, not in dollars or units. That makes it easier to compare responsiveness across products, markets, and time periods with different price levels or quantities.
Common Elasticity Types
Type | What it measures | Example question |
|---|---|---|
Price elasticity of demand | Demand response to price | Will customers buy less if price rises? |
Price elasticity of supply | Supply response to price | Can producers increase output quickly? |
Income elasticity | Demand response to income | Does demand rise when income rises? |
Cross elasticity | Demand response to another good's price | Are two goods substitutes or complements? |
Elasticity also helps explain revenue effects. When demand is elastic, a price increase can reduce total revenue because quantity falls more than price rises. When demand is inelastic, revenue may rise after a price increase.
Businesses use elasticity to think about pricing power, promotions, product substitutes, and customer sensitivity. Policymakers use it to estimate the effect of taxes, subsidies, and regulations.
Limits and Misunderstandings
Elasticity is not fixed forever. It can change with time, availability of substitutes, consumer habits, product necessity, brand loyalty, income level, and market conditions.
It also depends on the range being measured. Demand may be inelastic for a small price change but more elastic after a large price change or over a longer period when buyers can adjust.
The Bottom Line
Elasticity is a practical way to measure responsiveness. It helps explain how prices, income, taxes, and substitutes can change behavior, revenue, and market outcomes, especially when decisions depend on how quickly people or firms can adjust.