# What does the following mean: "supply has positive elasticity”?

What confuses me in particular is that I always thought of the concept of ‘elasticity’ with respect to something. That is, supply of x can be elastic with respect to y.

Am I missing something?

• In context of supply or demand, elasticity generally refers to price elasticity. So the statement is actually supposed to be: "price elasticity of supply is positive". So as price increases, quantity supplied increases. Dec 8, 2020 at 2:55

Price elasticity of supply is: $$\frac{dQ_s}{dp}\frac{p}{Q_s}$$. Because supply slopes upward $$\frac{dQ_s}{dp}>0$$. $$Q_s$$ and $$p$$ are also positive so $$\frac{dQ_s}{dp}\frac{p}{Q_s}>0$$.
• @StatsScared no the elasticity is by definition $\frac{dQ_s/Q_s}{dp/p}$ as it is relative change in quantity over relative change in price but that can be rearranged to nicer looking formula: $\frac{dQ_s}{dp}\frac{p}{Q_s}$ Dec 15, 2020 at 18:55