Elasticity of Demand: Types, Factors & Applications

Core Concepts

1. Definition and Importance

Elasticity of demand measures the responsiveness of quantity demanded to changes in price, income, or other determinants. It helps businesses (hotels, restaurants, airlines) and policymakers (NTC, NEPSE) predict revenue changes when adjusting prices or demand conditions.

Key Formula: $$\text{Price Elasticity of Demand (PED)}=\frac{\%\text{ Change in Quantity Demanded}}{\%\text{ Change in Price}}$$

• Elastic (|PED| > 1): Demand changes more than price (e.g., luxury hotels, international flights).
• Inelastic (|PED| < 1): Demand changes less than price (e.g., salt, essential medicines).
• Unitary Elastic (|PED| = 1): % change in Qd = % change in P (e.g., branded soft drinks).

2. Types of Elasticity

A. Price Elasticity of Demand (PED)

B. Income Elasticity of Demand (YED)

Measures how demand changes with income changes. $$\text{YED}=\frac{\%\text{ Change in Qd}}{\%\text{ Change in Income}}$$

• Normal Goods (YED > 0):
  • Luxury (YED > 1): Fine dining (e.g., Kaiser Café), international tours.
  • Necessity (0 < YED < 1): Mid-range hotels, local transport (Pathao).
• Inferior Goods (YED < 0): Instant noodles, cheap local buses (as income rises, demand falls).

C. Cross-Price Elasticity of Demand (XED)

Measures how demand for Product A changes when Product B’s price changes. $$\text{XED}=\frac{\%\text{ Change in Qd of A}}{\%\text{ Change in Price of B}}$$

• Substitutes (XED > 0): Daraz vs. Hamrobazaar, Ncell vs. NTC.
• Complements (XED < 0): Printers & ink cartridges, flights & hotels.
• Unrelated (XED ≈ 0): Ice cream & laptops.

Factors Affecting Elasticity

mindmap
  root((Factors Affecting PED))
    Availability_of_Substitutes
      Many substitutes → Elastic
      Few substitutes → Inelastic
    Nature_of_the_Good
      Luxury → Elastic
      Necessity → Inelastic
    Proportion_of_Income
      High % of income → Elastic (e.g., holidays)
      Low % of income → Inelastic (e.g., salt)
    Time_Period
      Short-run → Inelastic (habits)
      Long-run → Elastic (adjustments possible)
    Durability_and_Storage
      Durable → Elastic (can wait)
      Perishable → Inelastic (e.g., fresh food)

Real-World Applications

1. Tourism and Hospitality

• Luxury Hotels (Elastic Demand):

  • Example: Hotel Yak & Yeti in Kathmandu.
  • If prices rise by 10%, demand may drop by 15% (PED = 1.5). Revenue falls.
  • Solution: Offer loyalty programs (e.g., repeat stays) to reduce elasticity.

• Budget Hotels (Inelastic Demand):

  • Example: Hotel Everest in Pokhara.
  • Price ↑ by 10% → Demand drops by 5% (PED = 0.5). Revenue rises.
  • Strategy: Focus on cost control, not price cuts.

2. Digital Payments (Khalti, eSewa)

• Cross-Price Elasticity:
  • If Ncell reduces mobile data prices, demand for Khalti transactions (which require data) may rise (XED > 0).
  • Nepal Rastra Bank (NRB) monitors this to prevent anti-competitive practices.

3. NTC and Telecom Pricing

• Income Elasticity:
  • 4G services (YED ≈ 1.2) are income-elastic. As middle-class income rises, demand for 4G grows faster.
  • Voice calls (YED ≈ 0.3) are necessity-driven; price hikes have minimal demand impact.

Worked Example: Daraz vs. Hamrobazaar

Scenario: Daraz increases the price of a popular smartphone from Rs. 20,000 to Rs. 25,000 (25% ↑). Quantity demanded falls from 1,000 units to 800 units (20% ↓).

Calculation: $$\text{PED}=\frac{-20\%}{25\%}=-0.8(\text{Inelastic})$$ Interpretation:

• Demand is inelastic (|PED| < 1).
• Revenue Impact:
  • Old revenue = 1,000 × 20,000 = Rs. 20M
  • New revenue = 800 × 25,000 = Rs. 20M (same revenue despite price ↑).
• Business Strategy: Daraz could increase prices further to boost profits, as demand is insensitive to price changes.

Exam Tip

1. Always state whether demand is elastic/inelastic before calculating revenue effects.
2. Memorize the 5 types of PED and their graph shapes (horizontal/vertical/steep/flat).
3. For YED/XED:
   • Substitutes → Positive XED.
   • Complements → Negative XED.
   • Luxury goods → YED > 1.
4. Real-world twist: In exams, tie examples to Nepal (e.g., "If NTC raises call rates by 10%, how will demand for WhatsApp calls change?").
5. Diagrams are key:
   • Draw shift vs. movement on demand curves.
   • Label elastic/inelastic regions clearly.

Visual Summary:

flowchart TD
    A["Price ↑"] -->|"Elastic"| B["Qd ↓ More"]
    A -->|"Inelastic"| C["Qd ↓ Less"]
    D["Income ↑"] -->|"Luxury Good"| E["Qd ↑ More"]
    D -->|"Necessity"| F["Qd ↑ Less"]
    G["Substitute Price ↑"] --> H["Qd of Original ↑"]
    I["Complement Price ↑"] --> J["Qd of Original ↓"]