interpretation of elasticity results
📊 8.1 Marketing Analysis – Elasticity
What is Elasticity?
Elasticity measures how much one variable changes in response to a change in another variable. In marketing we usually look at how the quantity demanded of a product reacts to changes in price, income or the price of other goods.
The basic formula is:
$E = \dfrac{\% \Delta \text{Quantity}}{\% \Delta \text{Price}}$
If you want to see the full derivation:
$$E = \frac{\Delta Q / Q}{\Delta P / P}$$
Types of Elasticity
| Type | Formula | Interpretation |
|---|---|---|
| Price Elasticity of Demand (PED) | $E_d = \dfrac{\% \Delta Q_d}{\% \Delta P}$ | How sensitive buyers are to price changes. |
| Income Elasticity of Demand (YED) | $E_y = \dfrac{\% \Delta Q_d}{\% \Delta I}$ | How demand changes when income changes. |
| Cross‑Price Elasticity of Demand (XED) | $E_{xy} = \dfrac{\% \Delta Q_x}{\% \Delta P_y}$ | How demand for one product reacts to the price of another. |
Interpreting Elasticity Values
| Elasticity Value | Meaning | Business Implication |
|---|---|---|
| $|E| > 1$ | Elastic – quantity changes more than price. | Price cuts boost sales volume; price hikes reduce sales significantly. |
| $|E| = 1$ | Unit‑elastic – quantity changes proportionally to price. | Total revenue stays roughly the same when price changes. |
| $|E| < 1$ | Inelastic – quantity changes less than price. | Price increases can raise revenue; price cuts may hurt revenue. |
Practical Example: Soda Sales
Imagine a soda company that sells 10,000 cans per month at £1.00 each. A 10% price increase (to £1.10) leads to a 5% drop in quantity sold (to 9,500 cans).
- Calculate the percentage change in quantity: $\% \Delta Q = \frac{9,500 - 10,000}{10,000} \times 100 = -5\%$.
- Calculate the percentage change in price: $\% \Delta P = \frac{1.10 - 1.00}{1.00} \times 100 = 10\%$.
- Compute PED: $E_d = \frac{-5\%}{10\%} = -0.5$.
Interpretation: $|E_d| = 0.5 < 1$, so demand is inelastic. The company can raise prices slightly to increase revenue.
Quick Tips for Students
- Always keep the sign in mind – negative for demand, positive for supply.
- Use emojis to remember: 📈 for elastic (big change), 📉 for inelastic (small change).
- When in doubt, think of a real product: luxury cars are usually elastic, basic groceries are inelastic.
- Remember that elasticity can change over time – keep data updated!
Quiz Yourself
1️⃣ If a product’s price drops by 20% and quantity demanded rises by 40%, what is the PED?
2️⃣ What does a positive cross‑price elasticity indicate about two products?
Answer these to test your understanding before moving on to the next topic!
Revision
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