Research on the Influence of Emission Trading System on Enterprises' Green Technology Innovation

Table 3

Robustness test.

Variable	(1)	(2)
	Exclude the year when the policy is launched	PSM estimation
did	1.3368	1.3198
	(0.4141)	(0.4112)
Treat	−2.7202	−2.7290
	(0.6495)	(0.6465)
Post	0.9821	0.9545
	(0.5109)	(0.5029)
Control variable	Controlled	Controlled
Time fixed effect	Controlled	Controlled
Region fixed effect	Controlled	Controlled
N	12602	13014
R2	0.6448	0.6462