6.2. Price Elasticity of Supply (PES)

Price Elasticity of Supply (PES) measures how much the quantity supplied changes with a change in price.

Price Elasticity of Supply (PES) is an important concept in microeconomics that quantifies the responsiveness of the quantity supplied of a product to changes in its price. It tells us how much more or less of a good producers are willing to sell when the price goes up or down. Essentially, if a small change in price leads to a large change in the quantity supplied, then we say supply is elastic. Conversely, if a change in price results in a small change in the quantity supplied, it's called inelastic.

Think of a small bakery that makes cupcakes. If the price of cupcakes increases from $2 to$3, the bakery might be able to make and sell a lot more cupcakes quickly because they can buy more ingredients and hire more staff. This shows elastic supply. In contrast, if a farmer grows apples and the price changes, but it takes longer to grow more apples due to the growing season, the supply is less responsive, demonstrating inelasticity.

The terms elastic and inelastic describe how responsive the supply of a good is to changes in price.

Elastic supply occurs when a small increase in price results in a large increase in quantity supplied. This often happens in industries where producers can easily adjust their output. For example, a clothing company can quickly increase production to meet higher demand. On the other hand, inelastic supply is when changes in price do not significantly affect the quantity supplied. This is common in industries that require long production times or are constrained by factors such as natural growth or production capacity, like farming or oil extraction.

Consider a concert venue. If ticket prices for a concert increase, the venue manager can sell more tickets (elastic), as they have the capacity to accommodate more guests quickly. However, if ticket prices drop, they can't increase the number of seats available (inelastic) since they are fixed by the building's design.

Several factors influence the price elasticity of supply, including production time, availability of resources, and mobility of factors of production.

The price elasticity of supply can be influenced by various factors. The time period considered is crucial; in the short term, producers may not be able to increase supply quickly due to existing constraints. For example, a factory with machinery running at full capacity may find it hard to increase production immediately. In the long term, however, companies can invest in new technology or resources, making supply more elastic. The availability of raw materials also plays a role; if materials are abundant, producers can easily increase production. Additionally, if the factors of production (like labor and capital) can be easily moved or adjusted, the supply response will be more elastic.

Imagine a shoe manufacturer. If demand for a certain type of shoe suddenly spikes, the company can’t quickly increase production due to the time required to gather materials or hire additional workers in the short run (inelastic). However, over a few months, they can set up new production lines or source more materials, making their supply elastic.

Price elasticity of supply is calculated using the formula: PES = % Change in Quantity Supplied / % Change in Price.

PES is quantified using a simple formula: to find PES, you divide the percentage change in quantity supplied by the percentage change in price. This gives a numerical value that indicates how responsive the supply is to a price change. If the PES is greater than 1, supply is considered elastic; if it is less than 1, it is inelastic, and if it equals 1, supply is unitary elastic.

For example, if a farmer usually supplies 100kg of tomatoes and the price increases from $2 to$3 (a 50% price increase), and as a result, the farmer supplies 150kg (a 50% increase in quantity), we can calculate PES: PES = (50% increase in quantity) / (50% increase in price) = 1. Here, the supply is unit elastic. If the price increase caused the quantity supplied to double instead (to 200kg), PES would be 2, signaling an elastic response.

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