|
| (1) | (2) | (3) |
| 变量 | Op法 | Op法 | Op法 |
| IPR | 1.164*** | 1.063*** | 1.310*** |
|
| (206.74) | (159.03) | (159.02) |
| Pat |
|
| 0.009* |
|
|
|
| (1.66) |
| netprofit |
| 0.057*** | 0.057*** |
|
|
| (7.32) | (7.28) |
| size |
| 5.685*** | 5.562*** |
|
|
| (17.39) | (16.59) |
| Lev |
| 0.497*** | 0.499*** |
|
|
| (9.81) | (9.86) |
| Earning |
| −0.019 | −0.018 |
|
|
| (−1.63) | (−1.58) |
| First |
| −0.000 | −0.000 |
|
|
| (−0.36) | (−0.32) |
| TQ |
| −0.051*** | −0.051*** |
|
|
| (−11.41) | (−11.40) |
| ROA |
| 1.532*** | 1.527*** |
|
|
| (7.60) | (7.58) |
| Year | 控制 | 控制 | 控制 |
| Constant | 1.122*** | −17.321*** | −16.957*** |
|
| (40.06) | (−18.65) | (−17.77) |
| Observations | 8835 | 7977 | 7977 |
| R-squared | 0.969 | 0.977 | 0.977 |
| Number of code | 762 | 762 | 762 |
| Company FE | YES | YES | YES |
| F test | 0 | 0 | 0 |
| r2_a | 0.966 | 0.975 | 0.975 |
| F | 22,958 | 16,382 | 15,567 |