What term describes the responsiveness of quantity demanded to a change in income?

The term that describes the responsiveness of quantity demanded to a change in income is income elasticity of demand. This concept measures how much the quantity demanded of a good responds to changes in consumer income. When income increases, consumers may buy more of certain goods, especially normal goods, or buy less of inferior goods.

Income elasticity of demand can be either positive or negative. A positive value indicates that the good is a normal good, meaning that demand increases as income increases. Conversely, if the elasticity is negative, it indicates that the good is considered inferior, where demand falls as income rises.

In contrast, the other terms refer to different aspects of demand. Cross elasticity of demand focuses on how the quantity demanded of one good changes in response to the price change of another good. Price elasticity of demand measures how responsive the quantity demanded is to a change in the price of the same good. Non-price elasticity is a broader and less common term that may refer to the impacts of factors other than price on demand but does not specifically address income changes. Thus, income elasticity of demand is the precise term for the relationship between quantity demanded and changes in income.