Table 5. DID Estimations by excluding large cities.
| Total patent | Extensive margin | Intensive margin | |||
|---|---|---|---|---|---|
| Patent number | W_Citation | Firm number with patent | Innovation intensity | W_Citation | |
| (1) | (2) | (3) | (4) | (5) | |
| HSR | 0.408*** | 0.350*** | 0.309*** | 0.114*** | 0.134*** |
| (0.0456) | (0.0460) | (0.0298) | (0.0386) | (0.0450) | |
| Controls | Yes | Yes | Yes | - | - |
| County/firm fixed effects | Yes | Yes | Yes | Yes | Yes |
| Province-Year fixed effects | Yes | Yes | Yes | Yes | Yes |
| Number of counties/firms | 1,900 | 1,900 | 1,900 | 72,266 | 72,266 |
| R2 | 0.854 | 0.836 | 0.873 | 0.316 | 0.337 |
| Observation | 24,700 | 24,700 | 24,700 | 655,419 | 655,419 |
Notes: *, **, *** refers to the statistical significance at 10%, 5%, and 1%, respectively. The standard errors are reported in parentheses and clustered at county and firm levels.