169 NTU Management Review Vol. 31 No. 2 Aug. 2021 Panel B: DID Regression Results for Adjusted Patent Citations: Inter-industry Analysis One Matched Firm Two Matched Firms Three Matched Firms Four Matched Firms (1) (2) (1) (2) (1) (2) (1) (2) Treatmenti -0.0602** -0.0624** -0.0846*** -0.0892*** -0.0943*** -0.0986*** -0.0797*** -0.0825*** (0.0113) (0.0140) (0.0039) (0.0041) (0.0026) (0.0034) (0.0056) (0.0076) Aftert × Treatmenti 0.0693** 0.0730** 0.0829** 0.0817** 0.0675* 0.0646 0.0591 0.0511 (0.0212) (0.0218) (0.0236) (0.0316) (0.0842) (0.1166) (0.1024) (0.1807) LN (1+NetSalest-1) 0.0041 0.0040 0.0050 0.0049 0.0092*** 0.0096*** 0.0084*** 0.0089*** (0.1087) (0.1484) (0.1215) (0.1498) (0.0057) (0.0067) (0.0043) (0.0042) RDt-1 0.0019*** 0.0019*** 0.0036*** 0.0035*** 0.0052*** 0.0052*** 0.0048*** 0.0047*** (0.0001) (0.0002) (0.0000) (0.0000) (0.0000) (0.0000) (0.0000) (0.0000) Tobin’s Qt-1 -0.0008 0.0022 0.0034 0.0050* (0.6933) (0.3806) (0.2308) (0.0567) Observations 1,037 996 1,643 1,571 2,205 2,102 2,807 2,687 Adjusted R2 0.0552 0.0563 0.0641 0.0678 0.0853 0.0889 0.0807 0.0845 Note: This table presents the panel regression results of the inter-industry analysis, including the regression of R&D investment and adjusted citations with one, two, three and four matching control firms. The dependent variable of Panel B is the natural logarithm of 1+adjusted patent citation, i.e. LN (1+adjusted patent citation). The regression is shown in equation (1) of Section 3.3.4. Aftert = 1 if the firm is in the approval year or after approval year and 0 otherwise; Treatmenti = 1 if the firm is in the treated group and 0 otherwise. The treated firms are approved biopharmaceutical firms and control firms are high-tech firms. The definitions of the variables are presented in Appendix Table A1. Numbers in parentheses are p-values.***,**, and * denote significance at the 1%, 5%, and 10% levels, respectively. Panel B of Table 8 shows significantly negative coefficients for Treatment, indicating that the approved biopharmaceutical firms have lower adjusted patent citations than the high-tech firms. In this panel, the coefficients of interaction term, After×Treatment, are positive significantly for one and two matched firms and are not significant for three and four matched firms. These results imply that approved biopharmaceutical firms are motivated more than high-tech firm to improve their innovation quality by the Biopharmaceutical Act, but the results are less significant. In sum, both results of DID estimator and DID regression show that relative to highTable 8 DID Regression Results: Inter-industry Analysis (cont.)
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