| (1) | (2) | (3) | (4) | |
|---|---|---|---|---|
| 二线 | 三线 | 四线 | 五线 | |
| DID | -0.163 | 0.044 | 0.166*** | 0.061* |
| (0.101) | (0.037) | (0.029) | (0.032) | |
| _cons | 5.382* | 1.119 | 0.399 | -0.104 |
| (2.981) | (0.708) | (1.334) | (0.580) | |
| 控制变量 | YES | YES | YES | YES |
| 个体固定 | YES | YES | YES | YES |
| 年份固定 | YES | YES | YES | YES |
| N/条 | 463 | 1072 | 1198 | 1168 |
| adj. R2 | 0.814 | 0.827 | 0.770 | 0.737 |
