| Variable | Name | Symbol | Variable definition |
| explain variable | R & D investment intensity | RDI | R & D investment/main business revenue |
| R & D personnel input intensity | RDP | R & D personnel/total number of enterprises | |
| explained variable | total return on assets | ROA | net profit/average total assets explained |
| control variable | scale of company | SIZE | the natural logarithm of the total assets |
| asset-liability ratio | LEV | liabilities/assets |