Price Elasticity of Supply (Microeconomics)

This will be the last elasticity post for a while, i promise...

Right, so price elasticity of supply is sometimes referred to as PES. It measures the responsiveness of supply to a change in price. Basically, it indicates the amount a supplier is willing to to provide to a market after a change in price. The aim of a supplier is to maximise profits, so therefore the price elasticity of a supply should always be positive (If the price of a good increase so should supply, and vice versa.)

The formula for PES goes like this:

PES = % Change in quantity supplied ÷ % Change in price

As stated previously, the result will almost always be positive as it's highly unlikely that if price falls then suppliers will supply more of a good to the market. The figures gained from the formula are once again important:

• Greater than 1. If the result is over 1 then it tells us that the goods price elasticity of supply is elastic. So a price rise will lead to a more than responsive rise in supply.
• Between 0 and 1. If the result is between 0 and 1 then the goods price elasticity of supply is inelastic. This means a price rise will lead to a less than responsive rise in supply.
• Exactly 1. If the result is 1 then the goods price elasticity of supply is unitary. A change in price leads to an exactly proportional change in supply.

There are three main determinants of the price elasticity of supply of a good. The first is time period. If it takes a lot of time to adjust the supply of a good then it's likely the goods PES will be inelastic. An example of this would be Christmas trees with the long growing period. The next determinant is availability of factors of production. If there is no spare resources or labour to increase production then the PES is likely to be inelastic, and vice versa. Finally, availability of stocks of a product. If a supplier has plenty of goods stored away that can be added to the market should price change then the PES will likely be elastic. If there is no way of storing, or isnt any stored, PES will likely be inelastic. 

An example as usual. The price of shampoo increases by 22% over a period of time, over the same period suppliers supply 15% more shampoo to the market.

PES = 15% ÷ 22% = 0.68

This tells us that the PES of the shampoo is inelastic, suggesting that maybe it takes a long time to produce, there was no extra stored away or there is no spare factors of production. 

That's all for price elasticity of supply.