Departamento de Ingeniería Hidráulica Y Ambiental, Pontificia Universidad Católica de Chile, Avda. Vicuña Mackenna, 4860, Santiago, Chile.
Department of Business, New York College, Leoforos Vasilisis Amalias 38, 105 58, Athens, Greece.
Environ Sci Pollut Res Int. 2022 Mar;29(11):16727-16738. doi: 10.1007/s11356-021-16975-9. Epub 2021 Oct 16.
Several methodological approaches have been applied to evaluate the performance of water companies for regulatory purposes. Performance assessment involving a long-time period is relevant to consider the heterogeneity of the water companies as many changes might have occurred across years. In this study, we applied three different parametric models to estimate cost efficiency scores for a sample of English and Welsh water companies over the years 1991-2018. Two out of three models employed allowed us to decompose overall cost efficiency (OCE) into persistent and transient cost efficiency, i.e. allow identifying the drivers of OCE. The assessment covered six price reviews, and therefore, OCE estimations were linked with water industry regulation. Results revealed that OCE scores are sensitive to model specification as the average values for models 1, 2 and 3 were 0.959, 0.514 and 0.669, respectively. Nevertheless, the three models converge in identifying the source of raw water as an environmental variable affecting OCE. Cost efficiency estimations evidenced that price reviews conducted in 1999 and 2004 were challenging for water companies as OCE scores decreased. The opposite effect was identified for the subsequent price reviews. Beyond the estimated OCE score for the empirical application carried out, this study highlights the importance of selecting robust and adequate methods to evaluate the performance of water companies considering the main objective of such evaluation.
已经应用了几种方法学方法来评估水务公司的监管绩效。对于涉及长时间的绩效评估，考虑到水司之间的异质性是相关的，因为多年来可能发生了许多变化。在这项研究中，我们应用了三种不同的参数模型来估算 1991-2018 年间英国和威尔士水司的成本效率得分。其中两种模型允许我们将总体成本效率（OCE）分解为持久和瞬态成本效率，即识别 OCE 的驱动因素。评估涵盖了六次价格审查，因此，OCE 估算与水行业监管相关联。结果表明，OCE 得分对模型规范敏感，模型 1、2 和 3 的平均得分分别为 0.959、0.514 和 0.669。尽管如此，这三个模型在识别原水来源作为影响 OCE 的环境变量方面达成了一致。成本效率估算表明，1999 年和 2004 年进行的价格审查对水司来说是具有挑战性的，因为 OCE 得分下降了。随后的价格审查则产生了相反的效果。除了对所进行的实证应用进行的估计 OCE 得分外，本研究还强调了选择稳健和适当的方法来评估水司的绩效的重要性，这要考虑到此类评估的主要目标。
