ABSTRACT

In regulated industries, such as the water industry, it is of great significance to estimate productivity change as it helps policy makers to evaluate the effectiveness of regulatory regime and industry performance. In this paper, and for the first time, a translog input distance function was used to estimate and decompose productivity change into several components such as technical efficiency change, scale efficiency change, input-mix, and technical change. A further decomposition of technical change into neutral, output- and input-induced shifts of the frontier is provided. The above decomposition was applied to the English and Welsh water and sewerage companies and water only companies over the years 1993–2016. The results indicated that over the entire period water industry’s productivity increased by 9% per year, mainly due to scale efficiency change, input mix and technical change. On average water only companies reported higher productivity gains than water and sewerage companies.

摘要

在受监管的行业，例如水行业，估计生产力变化具有重要意义，因为它有助于政策制定者评估监管制度的有效性和行业绩效。在本文中，首次使用 translog 输入距离函数将生产力变化估计并分解为几个组成部分，如技术效率变化、规模效率变化、投入组合和技术变化。提供了将技术变革进一步分解为中性的、由产出和投入引起的前沿转移。上述分解适用于 1993 年至 2016 年间的英国和威尔士供水和污水处理公司以及纯水公司。结果表明，在整个时期，水工业的生产率每年以 9% 的速度增长，主要是由于规模效率变化、投入组合和技术变化。平均而言，纯水公司报告的生产率提高高于供水和污水处理公司。