基于NDDF的我国各省用水效率测量及对外贸易影响因素分析

Measurement of Water-use Efficiency in China's Provinces Based on NDDF and Analysis of Foreign-trade Factors Influencing Water-use Efficiency

以全国各省污水排放量为非合意产出,运用非径向方向距离函数构建了2种用水效率指数来测量用水效率。通过构建Tobit模型分析了对外贸易等因素对用水效率的影响以及作用机制。结果表明:(1)我国各省市用水效率水平不高,地区间差异显著,整体趋势是先上升后下降再上升;(2)对外贸易通过进出口2种途径可显著提高用水效率;(3)对比UEI和WEPI 2种用水效率指数,通过控制产业结构、水资源禀赋和水价等因素后实证结果仍然稳健。

We took the sewage discharge of China＇s provinces as the non-consensual output,used non-radial direction distance function（NDDF） to build two water-use efficiency indexes for the measurement of water-use efficiency,and analyzed the influences and action mechanism of some foreign-trade factors and other factors on water-use efficiency through the constructed Tobit model.The results showed that：（1） The water-use efficiencies of China＇s provinces were not high,and their overall trend was ＂rising-decline-rising＂; there were significant differences in water-use efficiency among different provinces.（2） Foreign trade could significantly improve water-use efficiency through the two ways of import and export.（3） Through comparing the two water-use efficiency indexes UEI and WEPI,the empirical result was still robust after controlling such factors as industrial structure,water resource endowment and water price.