2.3 Price Elasticity of Supply

Chapter 2.3: Price Elasticity of Supply (PES)

2.3.1 Definition of Price Elasticity of Supply (PES)

Price elasticity of supply (PES) is an economic measure that shows how much the quantity supplied of a good changes in response to a change in its price. It indicates the responsiveness of producers to changes in market price and plays a key role in understanding how flexible supply is in the short and long term.

In simple terms, PES answers the question: If the price of a product rises or falls, how much will the quantity supplied increase or decrease in response?

2.3.2 Formula for and Calculation of Price Elasticity of Supply

The formula for calculating PES is:

PES = (% Change in Quantity Supplied) / (% Change in Price)

Steps to Calculate PES:

1. Identify the initial and new quantity supplied.

2. Identify the initial and new price.

3. Calculate the percentage change in quantity supplied.

4. Calculate the percentage change in price.

5. Use the formula to determine PES.

Worked Example:

• Initial price = $10

• New price = $12

• Initial quantity supplied = 100 units

• New quantity supplied = 140 units

% Change in Price = [(12 – 10) / 10] × 100 = 20%
% Change in Quantity Supplied = [(140 – 100) / 100] × 100 = 40%
PES = 40% / 20% = 2.0

This means supply is price elastic, because the PES is greater than 1.

2.3.3 Understanding the PES Coefficient

The value of the PES coefficient provides insights into how suppliers behave:

• PES > 1: Elastic Supply – Quantity supplied changes by a greater percentage than the price change. Suppliers are highly responsive.

• PES < 1: Inelastic Supply – Quantity supplied changes by a smaller percentage than the price change. Suppliers are not very responsive.

• PES = 1: Unitary Elastic Supply – Quantity supplied changes by exactly the same percentage as price.

• PES = 0: Perfectly Inelastic Supply – Quantity supplied does not change at all regardless of price changes.

• PES = ∞: Perfectly Elastic Supply – A tiny price change leads to infinite change in quantity supplied.

Note that the PES coefficient is always positive since price and quantity supplied move in the same direction.

2.3.4 Factors Affecting Price Elasticity of Supply

Several key factors determine how elastic or inelastic supply is in a given market:

1. Spare Production Capacity

If a firm has unused capacity, it can increase output quickly when prices rise. This makes supply more elastic.

2. Stock Levels

Firms with high inventories or raw material stocks can respond more easily to price changes, making supply more elastic.

3. Time Period

• Short Run: Supply tends to be inelastic because firms cannot change production levels easily.

• Long Run: Supply is more elastic since firms have more time to adjust all inputs, invest in technology, and hire workers.

4. Mobility of Factors of Production

The easier it is to switch resources (labor, capital, machinery) between different products, the more elastic supply becomes.

5. Production Time

Goods that take a short time to produce (e.g., handmade crafts, baked goods) tend to have more elastic supply. In contrast, goods that take months or years to produce (e.g., ships, real estate) have inelastic supply.

6. Nature of the Industry

Industries such as agriculture face natural constraints (climate, seasons), making their supply less elastic compared to manufactured goods.

7. Availability of Inputs

If inputs (like skilled labor or special machinery) are readily available, it is easier to increase output, resulting in higher elasticity.

2.3.5 Implications for Speed and Ease with Which Firms React to Market Changes

Understanding PES is crucial for businesses, policymakers, and economists because it indicates how well a firm can respond to changes in market conditions:

• High Elasticity of Supply:

• Firms can increase production rapidly when prices rise.

• Businesses can benefit from higher revenues in expanding markets.

• Helps prevent shortages during demand spikes.

• Low Elasticity of Supply:

• Firms struggle to increase output quickly.

• Can result in missed opportunities and higher prices.

• Might lead to customer dissatisfaction due to long wait times or stock-outs.

Firms can improve their elasticity of supply by:

• Investing in scalable production technology.

• Maintaining buffer stocks.

• Improving logistics and supply chain responsiveness.

• Hiring flexible or temporary labor.

In highly competitive markets, being able to respond quickly to price changes can determine a firm’s survival and profitability.

Key Takeaways

• PES helps measure how quickly and effectively producers can respond to price changes.

• A higher PES value indicates more responsive supply.

• The responsiveness of supply is influenced by production time, spare capacity, stock levels, and factor mobility.

• Understanding PES helps businesses make better production, pricing, and investment decisions.