关键词: 可持续公共采购, 寻租监管, 演化博弈, 奖励-惩罚机制

Abstract: Sustainable public procurement (SPP) refers to the requirement for government procurement activities to achieve the fundamental economic function of “value for money” while fully leveraging the sustainable policy function of guiding environmental protection and fulfilling social responsibilities. With the increasing scale of SPP, covert operations in the supply of sustainable products become more frequent. Issues such as the inadequacy of sustainable labeling systems, the absence of product standards, and the falsification of product certificates become more pronounced. The problem with “sustainable corruption” wherein procurement personnel and suppliers collude, shield each other, and conspire for rent-seeking, continues to hinder the rational operation of the public sector procurement chain.
   Existing research has explored the causes, harms, and necessity of regulatory measures in rent-seeking corruption within SPP. However, there is a scarcity of research at the mathematical level examining the mechanisms of rent-seeking and regulation, with a notable gap in the study of decision-making behavior in SPP. In light of this, this paper aims to analyze the dynamic evolution mechanisms of rent-seeking and regulatory behavior among regulatory authorities, procurement personnel, and suppliers in SPP. By constructing an asymmetric tripartite dynamic evolutionary game model, the paper discusses the evolutionary strategies and conditions of rent-seeking and regulation generated by various stakeholders in the purchase of sustainable products. The stability of equilibrium points is verified using a system dynamics model. To obtain the optimal solution for the model and optimize its stability, a dynamic reward-penalty mechanism is introduced to enhance the model, ultimately yielding the optimal evolutionary stable strategy.
   The research results indicate that, on the one hand, government regulatory costs, procurement personnel psychological expectations, rent-seeking profit space, and reward-penalty thresholds are critical factors influencing the evolution of the tripartite game. Reducing regulatory costs, raising psychological expectations of procurement personnel, and expanding the bidding scope contribute to lowering rent-seeking risks. On the other hand, by introducing a reward-penalty mechanism to stabilize the model, considering both rent-seeking probability and corruption level in the dynamic mechanism, the strategy combination of “government not to regulate, procurement personnel not to rent-seek, and suppliers to provide sustainable products” is the ultimately obtained evolutionary stable strategy, confirming the results deduced from the initial model.
   The research findings can provide the theoretical basis for optimizing the procurement decisions, procedures, and regulatory mechanisms of SPP sectors. Based on the analysis and conclusions above, this paper suggests establishing a tripartite network autonomy model involving regulatory authorities, procurement personnel, and suppliers for sustainable procurement in government. Before the formation of this mode, firstly, it is necessary to improve the reward and punishment mechanism to guide self-restraint and incentives for both buyers and suppliers. Secondly, there is a need to strengthen the education on integrity and professionalism of procurement personnel and improve government procurement regulatory systems. Thirdly, it is essential to broaden the scope of tendering and eliminate single-source bidding for non-specific products, thereby reducing the rent-seeking space for a few individual suppliers and lowering the possibility of collusion between both parties for rent-seeking.

Key words: sustainable public procurement, rent-seeking and supervision, evolutionary game, reward-punishment mechanism