Data Envelopment Analysis of Government Subsidy Efficiency in New Energy Vehicle Enterprises: A Semi-Parametric Approach
Authors: ZHANG Wei, LI Ming, WANG Fang
This study evaluates the efficiency of government subsidies in the new energy vehicle (NEV) sector using a three-stage Data Envelopment Analysis (DEA) model that integrates semi-parametric regression to control for environmental variables and statistical noise. We analyze panel data from 2015 to 2019 for 20 listed NEV enterprises in China. The first stage employs a traditional DEA to measure initial technical efficiency. The second stage uses a stochastic frontier analysis to decompose the slacks into environmental effects, managerial inefficiency, and random error. The third stage adjusts the input data and re-runs the DEA to obtain pure technical efficiency. Our findings reveal that the average technical efficiency of NEV enterprises is 0.743, indicating significant room for improvement. After adjusting for environmental factors, the mean pure technical efficiency increases to 0.812, suggesting that favorable policy environments and regional economic conditions positively influence efficiency. Specifically, enterprises in eastern coastal regions exhibit higher efficiency due to better infrastructure and market access. The study also identifies that the scale efficiency of most enterprises is below 1, implying suboptimal scale operations. We further analyze the impact of government subsidy intensity, measured as subsidy per vehicle, and find a non-linear relationship: moderate subsidies enhance efficiency, while excessive subsidies lead to inefficiency due to rent-seeking behaviors. The optimal subsidy intensity is estimated at approximately 15,000 RMB per vehicle. Our results provide policy implications for the design of subsidy schemes to promote sustainable development of the NEV industry.