Measuring water-used and production efficiency in China using the super-efficient directional distance function

This study employs the super-efficiency directional distance function (SDDF) to assess the productivity of each administrative region in China over the period 2013-2017. The focus is on exploring variations in gross domestic production and efficiency related to waste gas and wastewater discharge across regions. The inputs include labor, capitalization, energy usage, and total water consumption, with domestic gross production as the output, and total wastewater and exhaust gas discharges as unintended outputs. The findings highlight Beijing, Tianjin, Hainan, Qinghai, Guangdong, Shanghai, Jiangsu, and Shandong as the most efficient regions, while Zhejiang, Ningxia, Hunan, and others exhibit lower performance. Notably, Guangxi ranks lowest (0.631). Unlike traditional DDF models, the SDDF model provides a more accurate estimation of the production efficiency of all 30 administrative regions, and addresses the limitation of generating the same efficiency values of 1 simultaneously for multiple regions. The study emphasizes the need for inefficient regions to reduce water consumption and emissions and enhance productivity, offering valuable insights for policymakers in formulating environmental and production policies.