Research On Eco-efficiency Of Chinese Provinces Based On Data Envelopment Analysis(DEA)

China's economy has developed rapidly after implementation of its reform and opening up policy,and has achieved remarkable results.In the case of increasing economic volume,China's economic development has now entered into a new stage of medium-high growth.And its achievements are at the cost of too much element inputs such as labor force and capital.Compared with the developed countries,the output efficiency of China is still very low.At the same time,as the world's largest energy consumer and carbon dioxide(CO2)emitter,China has a major task of energy conservation and environmental protection.The efficiency evaluation theory has a long history,from the traditional expert evaluation method to some statistical and operational research methods,such as data envelopment analysis(DEA),they have been widely used in the efficiency evaluation.Some of the salient features of the DEA approach make it highly respected in the field of relative efficiency evaluation.In the past,the study of economic efficiency,environmental efficiency and eco-efficiency using DEA method was mainly to describe the economic performance,environmental performance or comprehensive performance of production activities in a separate model,and look at them in isolation.In this paper,we propose an integrated DEA model based on the modified directional distance function,which allows the desirable output and undesirable output to increase or decrease simultaneously but disproportionately.This makes us analyze eco-efficiency,economic efficiency and environmental efficiency in a single model.In particular,eco-efficiency portrays the economic and environmental performance of production activities,and we use the proposed integrated model to decompose eco-efficiency into two parts,one that characterizes the ability to obtain economic benefits,called economic efficiency,and the other describe the ability to control pollutant emissions,known as environmental efficiency.The advantage of decomposition is the ability to detect the sources of low eco-efficiency and thus we can propose more efficient strategies.To illustrate the feasibility of our approach,a case study of 30 provinces in China is presented.The results show that,in the traditional model,the economic efficiency,environmental efficiency and eco-efficiency of eastern China are higher than those of the central and western areas,and the south is higher than the north.Among the economic efficiencies,environmental efficiencies and eco-efficiencies of the east,central and west areas as well as north and south,there are significant differences.In the integrated model,the environmental efficiency and eco-efficiency of eastern China are significantly higher than that of the central and western areas,but the economic efficiency does not have this characteristic.The same is true of the south and the north.In addition,it can be found that the economic efficiencies of all provinces are generally high,and the environmental efficiencies are relatively uniform,which shows that the low environmental efficiency is the main cause of low eco-efficiency.At the same time,through the window analysis,we find that the economic efficiency of each area during 2008-2014 does not change significantly,but the environmental efficiency has been gradually improved.Finally,on the basis of the results of the study,we put forward some suggestions to improve the ecological level.