A tool used to measure the responsiveness of demand for a good or service to a change in consumer income, this metric is calculated by dividing the percentage change in quantity demanded by the percentage change in income. For example, if a 10% income increase leads to a 20% increase in the demand for a particular product, the income elasticity of demand for that product is 2. This numerical representation helps categorize goods as inferior (negative values), normal (positive values less than one), or luxury (positive values greater than one).
Understanding how demand fluctuates with income changes is crucial for businesses in forecasting sales, setting prices, and developing effective marketing strategies. Historically, this economic concept has provided valuable insights into consumer behavior and market dynamics, allowing for more informed decision-making across industries. Its application extends beyond commercial interests, informing government policy related to social welfare programs and economic development initiatives.