What income elasticity of demand is and how to calculate it

Income elasticity of demand (YED) measures the responsiveness of demand for a product to changes in consumers' incomes.

Formula for income elasticity of demand

$\text{Income elasticity of demand (YED)}=\frac{\text{percentage change in quantity demanded}}{\text{percentage change in income}}$

Where:

• Percentage change in quantity demanded = The proportional change in the amount of the product consumers buy (%)
• Percentage change in income = The proportional change in consumers' earnings (%)

Worked example - Calculating income elasticity of demand

When consumer incomes rise by 15%, demand for a particular brand of coffee increases by 21%. Calculate the income elasticity of demand for this product.

Step 1: Identify the values

• Percentage change in quantity demanded = 21%
• Percentage change in income = 15%

Step 2: Apply the formula

$\text{YED}=\frac{21}{15}=1.4$

Step 3: Interpretation

A YED of 1.4 means the coffee is a luxury good, as demand rises by a greater proportion than income.

The categories of goods based on income elasticity

Goods can be classified based on their YED values, which reflect how demand changes with income fluctuations.

Categories and their characteristics

• Inferior goods - These have a negative YED. Demand increases when incomes fall and decreases when incomes rise.
• Normal goods - These have a positive YED. Demand decreases when incomes fall and increases when incomes rise.
• Luxury goods - A subset of normal goods with YED greater than 1 (income elastic). Demand changes by a larger proportion than income.
• Necessities - Another subset of normal goods with very low positive YED (income inelastic).

Examples of income elasticity for different goods

Specific examples illustrate how YED applies to real products, showing the range of values and their implications for demand sensitivity.

Examples of different YED values:

• Inferior goods - Generic brands, public transport, instant noodles (negative YED)
• Necessities - Basic food items, utilities, healthcare (YED between 0 and 1)
• Luxury goods - Designer clothing, expensive cars, fine dining (YED greater than 1)

The business implications of income elasticity

Understanding YED allows businesses to adapt strategies to economic conditions.

Strategies during economic growth

• Focus on income-elastic products like luxuries.
• Develop premium versions of existing products.

Strategies during economic recession

• Focus on basic versions of products at lower prices.
• Companies selling inferior goods may need to increase output.

Implications for new product development

• During recession, new product development should target affordable products.
• During economic growth, new product development should target premium products.