Document Type : Original Article
Authors
1
Ph.D. Student, Department of Economics, Firoozkooh Branch, Islamic Azad University, Firoozkooh, Iran.
2
Assistant professor, Department of Economic, Firoozkooh Branch, Islamic Azad University, Firoozkooh, Iran.
10.48308/jimp.14.4.121
Abstract
Introduction and purpose: The petrochemical industry in Iran, as a flagship sector, plays a pivotal role in the national economy, supplying a substantial share of its output to downstream industries. In recent decades, advancements in technology and research within the petrochemical sector have led to substantial improvements, reducing costs and enhancing efficiency. Therefore, considering the importance of the petrochemical industry and its role in economic growth, this article aims to evaluate the efficiency of petrochemical companies using the bootstrap-DEA approach. This method provides statistical inference regarding technical efficiency criteria in non-parametric frontier models.
Methods: To achieve this objective, a comprehensive two-stage approach was adopted. First, input-oriented efficiency scores were estimated under the assumptions of constant, variable, and non-increasing returns to scale for all companies, using radial (Debro-Farrell efficiency) and non-radial (Russell efficiency) methodologies to provide a robust evaluation. Then, a non-parametric independence test was conducted to identify the appropriate bootstrap implementation approach. Finally, considering the test results, the efficiency scores of petrochemical companies were estimated using the bootstrap-DEA approach. The bootstrap process allows for bias estimation and the calculation of confidence intervals for initial estimates.
Findings: The results indicate that Tondgoyan Company achieved Debro-Farrell efficiency under all three scenarios: constant, variable, and non-increasing returns to scale. Additionally, Zagros and Fanavaran companies exhibited Debro-Farrell efficiency under variable returns to scale. However, 18 other companies were inefficient, with Ghadir Petrochemical Company displaying the worst performance, achieving an efficiency score of 0.68 under constant returns to scale. Bias-corrected radial technical efficiency scores across homogeneous, heterogeneous, and subsampling bootstrap methods revealed that none of the 21 petrochemical companies exhibited full technical efficiency. Among them, Fanavaran and Tondgoyan showed better performance, while Aria, Pardis, Shiraz, and Isfahan Oil companies demonstrated the lowest input-oriented technical efficiency. Output-oriented technical efficiency findings indicated that Tondgoyan and Zagros were efficient, while Ghadir had the worst performance, with an efficiency score of 1.37, signifying 37% excess input consumption. The results further demonstrate that radial efficiency estimates are prone to overestimation, as confirmed by heterogeneous smooth bootstrap and subsampling techniques.
Conclusion: One of the primary objectives of Iran's 7th Development Plan is achieving 8% economic growth, with 2.8% attributed to productivity and efficiency improvements in production factors, including capital, human resources, technology, and management. Emphasis has been placed on bolstering the value-added chain within the petrochemical industry. Therefore, attention to the development of midstream and downstream petrochemical industries through reinvesting revenues from the export of upstream products is crucial for completing the value chain of the petrochemical sector.
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