Table 9.
Results of the heterogeneity analysis.
| Variables | (1) | (2) | (3) | (4) | (5) | (6) |
|---|---|---|---|---|---|---|
| State-owned | Non-state-owned | New drug | Non-new drug | Strong market power | Weak market power | |
| Input | Input | Input | Input | Input | Input | |
| DID | 0.810 | 2.456*** | 2.805*** | −0.076 | 3.600*** | 0.385 |
| (1.40) | (3.14) | (3.71) | (−0.14) | (4.10) | (0.76) | |
| Observations | 360 | 888 | 804 | 444 | 684 | 540 |
| R-squared | 0.7513 | 0.7790 | 0.8090 | 0.7374 | 0.7994 | 0.7459 |
| Firm FE | YES | YES | YES | YES | YES | YES |
| Year FE | YES | YES | YES | YES | YES | YES |
| Control variables | YES | YES | YES | YES | YES | YES |
| Permutation test | −1.646***(p = 0.006) | −2.882***(p = 0.000) | −3.215***(p = 0.000) | |||
The empirical p values of the coefficient differences between the different groups are obtained using the permutation test with 1,000 bootstrap replications. This formula for the Lerner index is as follows: (Operating Revenue - Operating Costs - Sales Expenses - Administrative Expenses) / Operating Revenue × 100%. Robust t-statistics in parentheses, ***p < 0.01; **p < 0.05; *p < 0.1.