关键词: 技术异质性, 动态网络DEA, 不良贷款, 结转资产, 时滞效应, 银行效率

Abstract: At present, China's financial system still relies mainly on indirect financing. In the financial system dominated by indirect financing, the operational efficiency of commercial banks is directly related to the optimal allocation of financial resources in the whole society, and is also an important path for banks to achieve high-quality development. In order to enhance competitiveness and improve their own efficiency, banks have adopted different development positioning and business models to cope with the impact of the external environment. The differences in scale, development positioning, business model, ownership structure, etc. of banks can lead to heterogeneity in production technology. The calculation of bank efficiency is a relative concept, and the performance evaluation of decision-making units under specific production technology constraints cannot be compared with that of other decision-making units under different production technology constraints. Therefore, how to evaluate the efficiency of banks with production technology heterogeneity and its impact on their multi period operations is a question worthy of in-depth consideration and research.
Considering the phased characteristics of bank operations, a two-stage dynamic network DEA evaluation model consisting of four heterogeneous systems is constructed to address the technological heterogeneity and time lag effects of non-performing loans and carried over assets in the operation process of commercial banks in China. The above model is applied to evaluate the overall efficiency and production stage efficiency of four types of commercial banks in China from 2012 to 2019. From the perspectives of the entire cycle and each period, the impact of time delay effect on the continuous operational efficiency of commercial banks with technological heterogeneity is analyzed in depth. The changes in operational efficiency of heterogeneous banks during the continuous period and the reasons for their inefficiency are explored. Finally, the relative importance of the reasons for inefficiency affecting the overall efficiency of China's banking industry is explored using the constructed endogenous weights, and corresponding insights are obtained.
The research has found that: (1)there is a significant difference in bank efficiency due to technological heterogeneity. In terms of both stage efficiency and overall efficiency, the overall performance of urban commercial banks is better than the performance of the other three types of banks, while the performance of joint-stock banks and rural commercial banks is lower than the overall average level; (2)the efficiency of rural commercial banks in the fundraising stage is more negatively affected by the time delay of non-performing loans than that of the other three types of banks, while the efficiency of state-owned, urban commercial banks, and joint-stock banks in the fund utilization stage is more negatively affected by the time delay of asset transfer than that of rural commercial banks; (3)the overall efficiency of commercial banks in China and the efficiency of fund utilization have been improved to a certain extent. The efficiency of urban commercial banks and rural commercial banks has improved significantly, but the efficiency of fund raising has decreased, with joint-stock banks experiencing the largest decline; (4)the operational efficiency of commercial banks in our country is dominated by the efficiency of the fund utilization stage. The efficiency of the fund raising stage is more important for the overall efficiency of urban commercial banks than that of the other three types of banks. The efficiency of the fund utilization stage has the greatest impact on the overall efficiency improvement of joint-stock banks.

Key words: technological heterogeneity, dynamic network DEA, non-performing loans, carry-over asset, time-lag effect, bank efficiency