| (a) | (b) | (c) | (d) |
dlpatent | lpatent | lpatent | lpatent | |
L.inde_com | 0.797*** | 0.726*** | 0.726** | 0.888** |
| (3.00) | (2.78) | (2.00) | (2.01) |
L.log_Total | 0.519*** | 0.413*** | 0.413*** | 0.416*** |
| (31.06) | (13.81) | (7.14) | (6.83) |
L.cap_exp | 0.497** | 0.290 | 0.290 | 0.394 |
| (2.17) | (1.41) | (1.17) | (1.24) |
L.Leverage | −0.000373*** | 0.000579 | 0.000579*** | 0.000664*** |
| (−3.31) | (1.30) | (5.08) | (9.03) |
L.Borad_size | 0.0135 | 0.0175* | 0.0175 | 0.0308* |
| (1.59) | (1.81) | (1.12) | (1.90) |
L.logQ | 0.0734*** | 0.0163** | 0.0163* | 0.0114 |
| (4.65) | (2.27) | (1.88) | (0.93) |
year_pre2003 |
|
| −0.000230 | −0.000226 |
|
|
| (−1.24) | (−1.25) |
_cons | −9.834*** | −7.795*** | −7.336*** | −7.612*** |
| (−21.14) | (−11.64) | (−5.92) | (−5.86) |
N | 8185 | 8185 | 8185 | 8185 |
r2 | 0.202 | 0.189 | 0.189 | 0.191 |
Year fixed effects | Yes | Yes | Yes | Yes |
Firm fixed effects | No | Yes | Yes | Yes |
Trend control | No | No | Yes | Yes |
Control*bill | No | No | No | Yes |