Variable type | Variable name | Variable symbol | Variable declarations | |
Explained variable | Technological innovation | R & D intensity | Internal R & D expenditure of enterprises/Prime operating revenue | |
Explanatory variable | Environmental regulation | Command-and-control type | EI2 | Investment in regional industrial pollution source control projects /Gross industrial production of the region |
Economic incentive type | EI4 | Investment in environmental pollution control by province /GDP of each province | ||
Public participation type | EI6 | Frequency of environmental protection words in each province | ||
Control variable | Capital intensity | KI | Enterprise capital/Number of employees | |
Level of Internet development | Internet | Ln (the internet penetration rate * Length of optical cable) | ||
Enterprise Performance | ROA | Return on total assets of enterprises | ||
Degree of market competition | M | Herfindahl index of the industry in t year |