Computer Simulation Analysis of the Impact of National Macro Policies on the Construction of Planned Key Projects in Lanzhou City during the “First Five-Year Plan” Period

This paper takes the key projects planned during the First Five-Year Plan period in Lanzhou City as the research object, and systematically analyzes the influence mechanism and heterogeneity characteristics of the national macro policies on the performance of engineering construction based on historical statistical data and computer simulation technology. The panel dataset is constructed, the double difference model is used to quantify the direct impact of policies, and the Heckman two-step method is utilized to conduct the robustness test. Construct the key engineering construction performance assessment system and evaluate the engineering construction performance level using hierarchical analysis. Combine the system dynamics simulation and mediation effect analysis to reveal the role path of macro policies. It is found that the national macro policy has a significant positive impact on the performance of key engineering construction in Lanzhou, and the performance of the projects supported by the policy focus is improved by 1.25 units on average (in terms of fuzzy evaluation value) compared with the similar projects not directly covered by the policy. The coefficient of the policy interaction term (DID) for the state-owned enterprise group is 1.50 and significant at the 1% level, while the coefficient of the policy interaction term for the non-state-owned enterprise group is only 0.30 and fails the significance test (t=0.85). Expansionary monetary policy and tight fiscal policy act on engineering construction through macro leverage ratio, economic growth rate and other intermediary variables, forming a differentiated transmission path.