Price Elasticity of Supply (PES)

Definition
Per (Gans et al.) price elasticity of supply is a measure of how much the quantity supplied of a good responds to a change in the price of that good. Supply is said to be elastic if when calculated is >1, inelastic when <1, and unit elastic when =1.

Why It Matters
Firms with elastic supply can respond quickly to price changes, capturing revenue opportunities. Additionally, understanding PES helps predict how markets will adjust to shocks. (Ross)

Example
Over short periods, supply is often inelastic (beach front land).
Over long periods, supply is more elastic (factories can scale).

Limitation
One limitation of elasticity, per “Price Elasticity - the Decision Lab” (2025), is it assumes consumers are rational, which is the biggest criticism of economics. Reality isn’t black and white, instead it’s shaped by cognitive biases, emotions, and context. For example, our willingness to pay shifts with expectations and how we frame value in the moment, like how it feels to pay $7 for a coffee in the morning and then paying $7 for a cocktail at night. Human’s decisions aren’t always linear.

Work cited:
Gans, Joshua, et al. Principles of Microeconomics. South Melbourne, Victoria, Australia, Cengage Learning Australia, 2021.

Ross, Sean. “How Does Price Elasticity Affect Supply?” Investopedia, 17 Mar. 2022, www.investopedia.com/ask/answers/040615/how-does-price-elasticity-affect-supply.asp.

“Price Elasticity - the Decision Lab.” The Decision Lab, 2025, thedecisionlab.com/reference-guide/economics/price-elasticity.