Summary of Understanding Elasticity in Economics
Understanding Elasticity in Economics: A Student's Guide
Introduction
Price Elasticity of Supply (PES) measures how much the quantity supplied of a good changes when its price changes, holding all else constant. In simple terms: how responsive is supply to changes in price?
Definition: Price Elasticity of Supply (PES) is the percentage change in quantity supplied divided by the percentage change in price.
Basic Concepts
Formula and Signs
- Formula: $$\text{PES} = \dfrac{%\ \text{change in quantity supplied}}{%\ \text{change in price}}$$
- Since the supply curve is typically upward-sloping, PES will always be positive or zero.
Definition: If PES $>1$, supply is elastic; if PES $<1$, supply is inelastic; if PES $=0$, supply is perfectly inelastic; if PES $=\infty$, supply is perfectly elastic.
Interpretation
- PES > 1: Quantity supplied responds more than proportionally to price (elastic supply).
- PES < 1: Quantity supplied responds less than proportionally to price (inelastic supply).
- PES = 0: Quantity does not change even if price changes (vertical curve).
- PES = \infty: Price does not change even if quantity varies (horizontal curve).
Step-by-Step Practical Example
Two apparel manufacturers, A and B, each sell garments at $10 and offer 100 units daily. Following a price increase to $12 due to higher demand:
-
Producer A: increases from 100 to 110 units.
- Change in quantity: $\dfrac{110-100}{100} = 0.10 = 10%$
- Change in price: $\dfrac{12-10}{10} = 0.20 = 20%$
- $$\text{PES}_A = \dfrac{10%}{20%} = 0.5$$ (inelastic supply)
-
Producer B: increases from 100 to 140 units.
- Change in quantity: $\dfrac{140-100}{100} = 0.40 = 40%$
- Change in price: $20%$ (same as above)
- $$\text{PES}_B = \dfrac{40%}{20%} = 2$$ (elastic supply)
💡 Did you know?Did you know that the same percentage price increase can lead to very different supply responses depending on the supplier's production capacity and resources?
Factors Affecting Supply Elasticity
- Time available to adjust production:
- In the short run, supply tends to be more inelastic; in the long run, it tends to be more elastic.
- Availability of factors of production (land, machinery, labor).
- Ease of storing the product (non-perishable products are more elastic).
- Idle capacity and technological flexibility.
- Ease of entry and exit for firms in the market.
Comparison Table: Elastic Supply vs. Inelastic Supply
| Characteristic | Elastic Supply | Inelastic Supply |
|---|---|---|
| Percentage change in quantity | Greater than the change in price | Less than the change in price |
| Adjustment time | Long or sufficient | Short or limited |
| Storage | Easy (non-perishable) | Difficult (perishable) |
| Typical example | Manufactured goods with idle capacity | Perishable agricultural products |
Extreme Cases: PES = 0 and PES = \infty
- PES = 0 (perfectly inelastic): The supply curve is vertical. Example: perishable flowers available at a given moment; the quantity cannot be increased even if the price rises.
- PES = \infty (perfectly elastic): The supply curve is horizontal. The producer sells any quantity at price P but will not accept a lower price.
Applied Activities (Quick Guide)
- Analyze the following table (provided in the original text) and draw the supply curve. Calculate the PES when the price falls from $90 to $80 and then to $50 per sack using the previous formula.
- In pairs, discuss why producers A and B from the example section have different PES. Consider: production capacity, ease of hiring labor, access to inputs, seasonality.
Real-world Case Study: Cashews in Tanzania
- Production depends on climate and investment in plantations, which makes supply unpredictable and can be relatively inelastic in the short term.
- The government sets guide prices to reduce volatility and, in surplus years, buys up stocks to protect producers.
- Adding local processing capacity could increase long-term elasticity and add value to exports.
💡 Did you know?Fun fact: Tanzania is one of th
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Elasticity of Supply
Klíčové pojmy: PES = percentage change in quantity supplied divided by percentage change in price, PES > 1 indicates elastic supply; PES < 1 indicates inelastic supply, PES is always non-negative for the upward-sloping supply curve, Example: if price rises by 20\% and quantity increases by 40\% then PES = 2, PES = 0 corresponds to perfectly inelastic supply (vertical curve), PES = \infty corresponds to perfectly elastic supply (horizontal curve), Factors that increase PES: longer time horizon, easy storage, idle capacity, Factors that reduce PES: perishable goods, shorter time horizon, scarcity of inputs
## Introduction
Price Elasticity of Supply (PES) measures how much the quantity supplied of a good changes when its price changes, holding all else constant. In simple terms: how responsive is supply to changes in price?
> **Definition:** Price Elasticity of Supply (PES) is the percentage change in quantity supplied divided by the percentage change in price.
## Basic Concepts
### Formula and Signs
- Formula: $$\text{PES} = \dfrac{\%\ \text{change in quantity supplied}}{\%\ \text{change in price}}$$
- Since the supply curve is typically upward-sloping, PES will always be positive or zero.
> **Definition:** If PES $>1$, supply is elastic; if PES $<1$, supply is inelastic; if PES $=0$, supply is perfectly inelastic; if PES $=\infty$, supply is perfectly elastic.
### Interpretation
- PES > 1: Quantity supplied responds more than proportionally to price (elastic supply).
- PES < 1: Quantity supplied responds less than proportionally to price (inelastic supply).
- PES = 0: Quantity does not change even if price changes (vertical curve).
- PES = \infty: Price does not change even if quantity varies (horizontal curve).
## Step-by-Step Practical Example
Two apparel manufacturers, A and B, each sell garments at $10 and offer 100 units daily. Following a price increase to $12 due to higher demand:
- Producer A: increases from 100 to 110 units.
- Change in quantity: $\dfrac{110-100}{100} = 0.10 = 10\%$
- Change in price: $\dfrac{12-10}{10} = 0.20 = 20\%$
- $$\text{PES}_A = \dfrac{10\%}{20\%} = 0.5$$ (inelastic supply)
- Producer B: increases from 100 to 140 units.
- Change in quantity: $\dfrac{140-100}{100} = 0.40 = 40\%$
- Change in price: $20\%$ (same as above)
- $$\text{PES}_B = \dfrac{40\%}{20\%} = 2$$ (elastic supply)
> Did you know that the same percentage price increase can lead to very different supply responses depending on the supplier's production capacity and resources?
## Factors Affecting Supply Elasticity
- Time available to adjust production:
- In the short run, supply tends to be more inelastic; in the long run, it tends to be more elastic.
- Availability of factors of production (land, machinery, labor).
- Ease of storing the product (non-perishable products are more elastic).
- Idle capacity and technological flexibility.
- Ease of entry and exit for firms in the market.
Comparison Table: Elastic Supply vs. Inelastic Supply
| Characteristic | Elastic Supply | Inelastic Supply |
|---|---:|---:|
| Percentage change in quantity | Greater than the change in price | Less than the change in price |
| Adjustment time | Long or sufficient | Short or limited |
| Storage | Easy (non-perishable) | Difficult (perishable) |
| Typical example | Manufactured goods with idle capacity | Perishable agricultural products |
## Extreme Cases: PES = 0 and PES = \infty
- PES = 0 (perfectly inelastic): The supply curve is vertical. Example: perishable flowers available at a given moment; the quantity cannot be increased even if the price rises.
- PES = \infty (perfectly elastic): The supply curve is horizontal. The producer sells any quantity at price P but will not accept a lower price.
## Applied Activities (Quick Guide)
1. Analyze the following table (provided in the original text) and draw the supply curve. Calculate the PES when the price falls from $90 to $80 and then to $50 per sack using the previous formula.
2. In pairs, discuss why producers A and B from the example section have different PES. Consider: production capacity, ease of hiring labor, access to inputs, seasonality.
## Real-world Case Study: Cashews in Tanzania
- Production depends on climate and investment in plantations, which makes supply unpredictable and can be relatively inelastic in the short term.
- The government sets guide prices to reduce volatility and, in surplus years, buys up stocks to protect producers.
- Adding local processing capacity could increase long-term elasticity and add value to exports.
Fun fact: Tanzania is one of th