Can Network Infrastructure Construction Drive New Quality Productivity? ——A Quasi-Natural Experiment Based on the “Broadband China” Strategy

The level of new quality productivity in cities: constructed based on the connotation of new quality productivity3 first-level indicators of a new type of workers, new type of labor objects, and new type of labor materials. For the new type of workers, two secondary indicators, namely the structure of workers and labor productivity, and four tertiary indicators are selected. The level of new labor means is mainly manifested in the production tools directly involved in production and the infrastructure and scientific and technological innovation indirectly involved in production, and the level of production tools, two tertiary indicators are selected, namely, the level of robot application and the big data trading platform; five tertiary indicators are selected in the level of infrastructure; and in the level of scientific and technological innovation, six tertiary indicators are selected, measured in terms of technological innovation inputs and technological innovation outputs. Indicators. The new labor object is reflected in the industrial structure and ecological environment level, selected industrial structure and ecological environment 2 secondary indicators, 9 tertiary indicators."Broadband China" policy pilot cities treat=1, non-pilot cities treat=0; the year of policy implementation and after period=1, before the implementation of the policy period=0.Control variables: the selected control variables include population density (lnpeop), measured by taking the logarithm of the total population of urban municipal districts; economic development level (lngdp), measured by taking the logarithm of the per capita gross domestic product (GDP); financial correlation rate (finan), measured by taking the ratio of the regional deposits and loan balances to the GDP; openness (open), measured by taking the ratio of the total amount of imports and exports to the GDP; the ratio of the total amount of exports to the GDP; the ratio of the total amount of imports to the GDP. Openness level (open), measured by the ratio of total imports and exports to GDP; fiscal size (fiscal), measured by the ratio of general government fiscal expenditure to GDP.Mediating variables: this paper takes technological innovation capacity (lninno) and total factor productivity (tfp) as mediating variables. The number of green patent applications is taken as a logarithm to measure the level of regional technological innovation; the data envelopment model with global reference is used to measure the total factor productivity of the city, with real GDP as the output; the number of employees in the secondary and tertiary industries is used as the labor input; and the stock of physical capital is used as the capital input.