| Variable type | Symbols | Meanings | Description |
| Dependent variables | LnY | Log value of gross output | Gross output replaced by gross annual sales |
| Explaining variables | DE | Direct export | Dummy variable: DE = 1, direct export; DE = 0, non-direct export |
| IDE | Indirect export | Dummy variable: IDE = 1 indirect export; IDE = 0, non-indirect export | |
| Control variables | FDI | Foreign direct investments | Dummy variable: FDI = 1, foreign direct investment available FDI = 0, no foreign direct investment |
| RD | Research and development investments | Dummy variable: RD = 1, R&D investments available in the last 3 years RD = 0, no R&D investments available in the last 3 years | |
| LnCU | Capital utilization | Ratio of actual outputs in current year in potential maximum outputs | |
| LnHU | Human capitals | Average years of education of staff | |
| LnAGE | Enterprise age | Existence years of enterprises | |
| RG | Region | Dummy variable: RG = 1, provincial capital, non-capital cities | |
| ID | Industry | Dummy variable |