Chapter 7: Concise

Chapter 7 Production Costs

• Production: Transformation of inputs into outputs.

  • Example Inputs: Land, Labor, Capital, Equipment, etc.

  • Example Outputs: Apples, Software.

• Production Function: $Q = f(X<em>1, X</em>2, …, X_n)$

  • Output $Q$ is dependent on inputs $X_i$.

Short Run vs Long Run

• Short Run (SR): At least one input is fixed (e.g., Capital).

  • Labor is flexible; Capital is fixed.

  • Timeframe can be long (e.g., 20 years).

• Long Run (LR): All inputs variable.

  • Capital can be variable depending on events (e.g., disasters).

Key Concepts in Short Run

• Total Product of Labor (TPL): $TPL = Q$

• Average Product of Labor (APL): $APL = \frac{Q}{L}$

• Marginal Product of Labor (MPL): $MPL = \frac{\Delta Q}{\Delta L}$

• Law of Diminishing Returns: Beyond a point, additional variable input yields less output.

  • Applies only in Short Run.

Cost Structure

• Costs:

  • Fixed Cost (TFC): Associated with fixed inputs.

  • Variable Cost (TVC): Associated with variable inputs.

  • Total Cost (TC): $TC = TFC + TVC$

• Average Costs:

  • Average Total Cost (ATC): $ATC = \frac{TC}{Q}$

  • Average Fixed Cost (AFC): $AFC = \frac{TFC}{Q}$

  • Average Variable Cost (AVC): $AVC = \frac{TVC}{Q}$

• Marginal Cost (MC): $MC = \frac{\Delta TC}{\Delta Q}$

Long Run Considerations

• Long Run Returns:

  • Increasing Returns to Scale (IRS): $LRAC$ decreases as output increases.

  • Constant Returns to Scale (CRS): Fixed efficiency as output increases.

  • Decreasing Returns to Scale (DRS): $LRAC$ increases as output increases.

• Optimal Output in Long Run:

  • $Q^*$ represents the equilibrium output for firms in perfect competition.

Types of Profit

• Profit: A = TR - TC

  • Accounting Profit: $TR - ext{Explicit Costs}$

  • Economic Profit: $TR - ( ext{Explicit Costs} + ext{Implicit Costs})$

Decision Making Example

• Example: Professor considering consulting business:

  • Accounting Profit: $85,000, Economic Profit: -$10,000.

  • Predicts not leaving university due to negative economic profit, despite accounting profit.