Private Costs And Benefits, Externalities And Social Costs And Benefits (Copy)

7.4.1 Definition and Calculation of Social Costs (SC)

• Private Costs (PC):
  • Costs borne directly by producers or consumers involved in the transaction.
  • Examples: wages, raw materials, utility bills.
• External Costs (EC):
  • Costs imposed on third parties or society that are not borne by the producer or consumer.
  • Examples: pollution, noise, traffic congestion.
• Social Costs (SC):
  • The total cost to society of producing or consuming a good or service.
  • Includes both private and external costs.
  • Formula:
    SC = PC + EC
• Marginal Concepts:
  • Marginal Private Cost (MPC): Additional private cost from producing one more unit.
  • Marginal External Cost (MEC): Additional external cost from producing one more unit.
  • Marginal Social Cost (MSC): Total additional cost to society from producing one more unit.
  • Formula:
    MSC = MPC + MEC

7.4.2 Definition and Calculation of Social Benefits (SB)

• Private Benefits (PB):
  • Benefits gained directly by consumers or producers from consuming or producing a good or service.
  • Examples: consumer satisfaction, profit for producers.
• External Benefits (EB):
  • Benefits enjoyed by third parties or society that are not paid for by the consumer or producer.
  • Examples: education improving societal skills, vaccinations reducing disease spread.
• Social Benefits (SB):
  • The total benefit to society from consuming or producing a good or service.
  • Formula:
    SB = PB + EB
• Marginal Concepts:
  • Marginal Private Benefit (MPB): Additional private benefit from consuming or producing one more unit.
  • Marginal External Benefit (MEB): Additional external benefit from one more unit.
  • Marginal Social Benefit (MSB): Total additional benefit to society from one more unit.
  • Formula:
    MSB = MPB + MEB

7.4.3 Definition of Positive Externality and Negative Externality

• Positive Externality:
  • When production or consumption of a good creates benefits for third parties not reflected in market prices.
  • Society gains more than private individuals.
  • Examples: education, vaccinations, public parks.
• Negative Externality:
  • When production or consumption imposes costs on third parties not reflected in market prices.
  • Society bears costs ignored by private individuals.
  • Examples: pollution, smoking, loud noise.

7.4.4 Positive and Negative Externalities of Consumption and Production

7.4.5 Deadweight Welfare Losses Arising from Externalities

• Deadweight Welfare Loss:
  • The loss of economic efficiency when equilibrium in a market is not socially optimal.
  • Caused by externalities leading to overproduction or underproduction.
• Negative Externality (Overproduction):
  • Market produces more than socially optimal quantity → social costs exceed social benefits.
  • Welfare loss represented by area between MSC and MPC curves from social optimum quantity to market quantity.
• Positive Externality (Underproduction):
  • Market produces less than socially optimal quantity → social benefits exceed social costs.
  • Welfare loss is area between MSB and MPB curves from market quantity to social optimum quantity.

7.4.6 Asymmetric Information and Moral Hazard

• Asymmetric Information:
  • Situation where one party in a transaction has more or better information than the other.
  • Leads to market failure as decisions are made based on incomplete or incorrect info.
  • Examples: used car sales, insurance markets.
• Moral Hazard:
  • When one party changes behaviour to the detriment of the other after a contract is made, because they do not bear full consequences.
  • Example: insured individuals taking greater risks because insurance covers loss.

7.4.7 Use of Costs and Benefits in Analysing Decisions

• Decisions should consider net social benefit, the difference between social benefits and social costs.
• Net Social Benefit = Social Benefit – Social Cost
• Rational decision-making requires accounting for external costs and benefits to maximise social welfare.
• Although net present value is not required, understanding long-term costs and benefits is crucial.

Diagrams

Diagram 1: Social Costs and Private Costs (Negative Externality)

Price/Cost
↑
|   MSC (Marginal Social Cost)
|     /
|    /    
|   /      
|  /         
| /             
|/____________________________ MPC (Marginal Private Cost)
|                   
|                  
|               Demand
|                   
|_____________________________→ Quantity

- MSC lies above MPC due to external costs.
- Market produces Qm > Q* (social optimum).

Diagram 2: Social Benefits and Private Benefits (Positive Externality)

Price/Benefit
↑
|   MSB (Marginal Social Benefit)
|     /
|    /    
|   /      
|  /         
| /             
|/____________________________ MPB (Marginal Private Benefit)
|                   
|                  
|               Supply
|                   
|_____________________________→ Quantity

- MSB lies above MPB due to external benefits.
- Market produces Qm < Q* (social optimum).

Diagram 3: Deadweight Welfare Loss

Price/Cost
↑
|   MSC
|   /|
|  / |   
| /  |    
|/---|---____ MPC
|    |        
|    |      Demand
|    |        
|    |_______________→ Quantity
|        Q*    Qm

- Triangle between Q* and Qm is deadweight welfare loss.

Diagram 4: Asymmetric Information

Buyer
↓
-------------------------
|  Seller has more info  |
|  about product quality |
-------------------------

- Leads to market inefficiency and potential failure.