8.1 - Price Elasticity of Demand
The concept and importance of elasticity of demand
Elasticity of demand measures how much the quantity demanded of a product changes in response to variations in factors such as price, promotional spending, or consumer income levels. It provides a way to quantify these relationships, helping businesses understand consumer behaviour.
Characteristics of demand curves and elasticity
Demand curves vary in their steepness, which affects how responsive quantity demanded is to price changes:
- Steeper curves show inelastic demand, where quantity demanded changes little with price shifts.
- Flatter curves indicate elastic demand, where quantity demanded is highly responsive to price changes.
Effects on total revenue
- For products with inelastic demand, increasing the price can raise total revenue, as the smaller drop in quantity demanded is outweighed by the higher price per unit.
- For products with elastic demand, increasing the price typically reduces total revenue, as the larger fall in quantity demanded more than offsets the price rise.
Calculating and interpreting price elasticity of demand
Price elasticity of demand (PED) quantifies how sensitive the quantity demanded is to changes in the product's price. It is calculated using percentage changes to allow comparisons across different products and price levels.
Formula for price elasticity of demand
PED values are usually negative due to the inverse relationship between price and quantity demanded (e.g., a price rise leads to a demand fall). However, the negative sign is often ignored, and the focus is on the absolute value for interpretation.
Interpreting PED values
- Perfectly inelastic (PED = 0) - Quantity demanded stays the same regardless of price changes (theoretical, e.g., a life-saving drug in an emergency).
- Inelastic (0 < PED < 1) - Quantity demanded changes by a smaller percentage than the price; revenue rises with price increases.
- Unit elastic (PED = 1) - Quantity demanded changes by the same percentage as the price; total revenue remains unchanged.
- Elastic (PED > 1) - Quantity demanded changes by a larger percentage than the price; revenue falls with price increases.
- Perfectly elastic (PED = infinity) - Quantity demanded is infinite at one price but zero at any higher price (theoretical, e.g., in perfect competition at market price).
Worked example - Calculating price elasticity of demand
A company sells 800 units of a product at £20 each. After raising the price to £24, sales fall to 640 units. Calculate the PED and interpret the result.
Step 1: Identify the values
- Old quantity = 800 units
- New quantity = 640 units
- Old price = £20
- New price = £24
Step 2: Calculate percentage changes
Percentage change in quantity demanded = (640 - 800) / 800 × 100 = -20%
Percentage change in price = (24 - 20) / 20 × 100 = 20%
Step 3: Apply the PED formula
Step 4: Interpretation
The absolute PED value is 1, indicating unit elastic demand. Total revenue will remain the same despite the price change.
Factors influencing price elasticity of demand
Several factors affect whether demand for a product is elastic or inelastic, influencing how consumers respond to price changes.
Key determinants of PED
- Necessity of the product - Essential items, such as water or basic medicines, often have inelastic demand because consumers need them regardless of price.
- Availability of close substitutes - Products with many alternatives, like a specific brand of coffee in a crowded market, tend to have elastic demand as consumers can easily switch.
- Strength of consumer loyalty - Strong brand loyalty, seen in popular smartphones or luxury watches, leads to inelastic demand as buyers are less likely to switch even if prices rise.
- Price relative to income - Low-cost items that form a small part of consumers' budgets, such as paper clips or rubber bands, usually have inelastic demand since price changes have minimal impact on overall spending.
The impact of price elasticity on business decisions
Understanding PED helps businesses make strategic choices, particularly in pricing and cost management, to optimise revenue and profitability.
Applications in pricing strategies
Firms can adjust prices based on PED to maximise revenue. For instance, an airline might increase fares on routes with inelastic demand (e.g., business travel where alternatives are limited) while lowering prices on elastic routes (e.g., leisure travel with many competitors) to attract more customers.
Applications in handling cost increases
Businesses selling products with inelastic demand can more easily pass on cost rises, such as wage increases, to consumers through higher prices without significant sales loss. For example, a specialist electronics retailer with loyal customers could absorb staff wage hikes by adjusting prices, maintaining profit margins.