Which of the following factors does NOT affect price elasticity of demand?

Price elasticity of demand measures how sensitive the quantity demanded of a good is to a change in its price. While several factors influence this sensitivity, the cost of production primarily impacts supply rather than the demand side of the market.

The availability of substitutes is crucial because if a good has many substitutes available, a price increase can lead consumers to easily switch to those alternatives, making demand more elastic. Similarly, the proportion of consumer income spent on the good affects demand elasticity; if consumers spend a larger portion of their income on a product, they are likely to be more sensitive to price changes. Finally, whether a good is considered a necessity or a luxury affects consumer behavior; necessities tend to have inelastic demand since people need them regardless of price, while luxury goods tend to have more elastic demand as consumers can forgo them if prices rise.

Therefore, since the cost of production affects supply rather than directly influencing the responsiveness of consumers to price changes, it does not play a role in determining the price elasticity of demand.