Table 10 Variable type and definitions.
Type | Variable | Symbol | Definition |
|---|---|---|---|
Explained variables | Energy-environmental efficiency | EEE | Measured by non-radial directional distance function |
Scale efficiency | SE | Measured by non-radial directional distance function | |
Pure technical efficiency | PTE | Measured by non-radial directional distance function | |
Explanatory variables | Green technology innovation | GTI | The sum of the number of green invention patent applications and the number of green utility patent applications |
Substantive green innovation | SubGI | Number of green invention patent applications | |
Symbolic green innovation | SymGI | Number of green utility patent applications | |
environmental regulation | ER | The proportion of the total emission fee to GDP | |
Control variables | Gross domestic product per capita | PGDP | The ratio of GDP to total population |
Industrial structure | IS | The value added to GDP ratio of secondary industry | |
Foreign direct investment | FDI | The ratio of foreign direct investment to GDP | |
Energy consumption structure | ECStruc | The ratio of coal usage to total energy consumption | |
Urbanization level | Urban | The ratio of urban living population to total population | |
R&D investment intensity | RDI | R&D expenditure | |
Energy intensity | EI | Energy consumption per unit of GDP | |
Fixed asset investment | Fix | Total investment in fixed assets | |
R&D personnel input | RDP | R&D full time equivalent |
