2003年-世界发展银行全球_A_Multioutput_Cost_Function_for_Port_Terminals___Some_Guidelines_for_Regulation_27页_283kb

Summary of "A Multioutput Cost Function for Port Terminals"

Core Content

This paper presents a multioutput cost function estimation for port terminals, specifically focusing on cargo handling activities at the Las Palmas port in Spain. The study aims to provide regulators with essential economic tools such as marginal costs, economies of scale, and economies of scope to improve the efficiency and regulation of port operations.

Main Viewpoints

• Multioutput Nature of Port Terminals:
  Cargo handling in ports is a multioutput activity, as it involves different types of cargo such as containers, bulk, and Ro-Ro (roll-on/roll-off) goods. The paper argues that these different cargo types should be treated as distinct products due to their varying handling processes and associated costs.

• Importance of Cost Analysis for Regulation:
  Understanding the cost structure of port terminals is crucial for regulators to set appropriate tariffs, assess efficiency, and determine the optimal level of service provision. The paper emphasizes that the multioutput nature of the activity must not be ignored, as it significantly affects cost calculations and regulatory decisions.

• Economies of Scale and Scope:
  The study introduces key economic concepts:

  • Economies of scale: Measure the cost efficiency gained from increasing production.
  • Economies of scope: Measure the cost efficiency from producing multiple products together rather than separately.
    These concepts are essential for determining whether diversification or specialization is more cost-effective for port terminals.

• Cost Function Estimation:
  The paper estimates a multioutput cost function using monthly data from three terminals at the Las Palmas port. This model helps in calculating product-specific marginal costs and economies of scale and scope.

Key Information

1. Data and Methodology

• The study uses monthly data from three terminals (T.1, T.2, T.3) in the Las Palmas port area from 1991 to 1999.
• The data includes:
  • Total monthly production expense
  • Monthly average production volume (in tons) for each product type
  • Product-specific costs and their variations
• The model considers four categories of productive factors:
  • Personnel: Divided into non-port workers and port workers (further classified into RLC and RLE workers).
  • Total area: Includes concession area and rented area.
  • Capital: Comprises buildings, machinery, and depreciation.
  • Intermediate consumption: Includes office supplies, utilities, and other operational costs.

2. Product-Specific Costs

• The three main products analyzed are:
  • General break-bulk cargo: Accounts for 9.9% of total monthly moved tons.
  • Containers: Accounts for 87.4% of total monthly moved tons.
  • Ro-Ro cargo: Accounts for 2.7% of total monthly moved tons.
• General cargo is identified as more expensive to handle, leading to a higher marginal cost than containers or Ro-Ro cargo.

3. Economies of Scale and Scope

• The paper defines economies of scale using the formula:
  $$
  S = \frac{C(Y)}{Y \nabla_y C(Y)}
  $$
  where $S > 1$ indicates increasing returns to scale.
• Economies of scope are calculated using:
  $$
  ED_T(Y) = \frac{1}{C(Y)} \left[ C(Y_T) + C(Y_{N-T}) - C(Y) \right]
  $$
  with $ED_T > 0$ indicating cost savings from producing multiple products together.
• The relationship between economies of scale and scope is given by:
  $$
  S_N(Y) = \frac{\alpha_T S_T(Y) + (1 - \alpha_T) S_{N-T}(Y)}{1 - ED_T(Y)}
  $$
  showing that economies of scope enhance overall economies of scale.

4. Empirical Findings

• The study finds that:
  • All three terminals exhibit increasing economies of scale at the point of approximation.
  • There are economies of scope, suggesting that diversification is more cost-effective than specialization.
  • General cargo has a higher marginal cost compared to other products, which may influence the decision on whether to specialize or diversify terminal operations.
• The data also reveals significant variability in production and costs across the study period, with some months having up to five times the average monthly production volume.

5. Comparison with Previous Studies

• The paper highlights that previous empirical studies on port cost functions have mostly focused on single-output models, often leading to conflicting results.
• It also notes that the multioutput cost function provides a more accurate representation of the actual cost structure, especially when economies of scope are present.

Conclusion

This study contributes to the understanding of the economic structure of port terminals by estimating a multioutput cost function. It provides regulators with the tools to better assess marginal costs and economies of scale and scope, which are essential for setting efficient tariffs and guiding port planning decisions. The findings emphasize the importance of considering the multioutput nature of port operations to avoid misleading conclusions and ensure effective regulation.