Table 2.

Baseline regression results.

Variables	(1)	(2)	(3)	(4)	(5)	(6)	(7)	(8)
	GrdE	GrdE	GrdE	GrdE	GopE	GopE	GopE	GopE
$\mathit{DID}$	0.163***	0.054***	0.013***	0.017***	0.162***	0.053***	0.017***	0.014**
	(0.003)	(0.003)	(0.005)	(0.006)	(0.003)	(0.003)	(0.006)	(0.006)
$\mathit{Age}$		0.003**	0.008**	0.007**		0.006***	0.011***	0.009***
		(0.001)	(0.004)	(0.004)		(0.001)	(0.003)	(0.003)
$\mathit{\text{Size}}$		−0.005***	−0.005	−0.005		−0.010***	−0.007**	−0.008**
		(0.001)	(0.003)	(0.003)		(0.001)	(0.003)	(0.004)
$\mathit{\text{Leverage}}$		−0.019***	−0.015	−0.017		−0.011*	−0.012	−0.014
		(0.006)	(0.013)	(0.013)		(0.006)	(0.010)	(0.011)
$\mathit{\text{Share}}$		−0.000	−0.000	−0.000		0.000	0.000	−0.000
		(0.000)	(0.000)	(0.000)		(0.000)	(0.000)	(0.000)
$\mathit{TFP}$		0.014***	0.008**	0.008**		0.018***	0.008**	0.010***
		(0.002)	(0.003)	(0.004)		(0.002)	(0.004)	(0.004)
$\mathit{\text{Digital}}$		0.001***	0.000	0.001		0.001***	0.000	0.001
		(0.000)	(0.000)	(0.001)		(0.000)	(0.000)	(0.001)
Number of clusters (City)		260
Observations	23,682	23,682	23,682	23,682	23,682	23,682	23,682	23,682
R-squared	0.097	0.359	0.551	0.561	0.097	0.361	0.546	0.557
Firm FE	No	No	Yes	Yes	No	No	Yes	Yes
Year FE	No	No	Yes	Yes	No	No	Yes	Yes
Prov × Year FE	No	No	No	Yes	No	No	No	Yes
Ind × Year FE	No	No	No	Yes	No	No	No	Yes

This table reports the baseline DID estimates of the AI Pilot Zone Policy on firms’ green R&D efficiency (GrdE) and green innovation output performance (GopE). The main regressor, DID, equals one for firms in pilot cities after policy implementation. All regressions are estimated via reghdfe, with standard errors clustered at the city level. Firm fixed effects account for time-invariant characteristics; year fixed effects capture nationwide shocks; province-by-year fixed effects absorb regional variations over time; and industry-by-year fixed effects control for sector-specific temporal trends. ***, **, and * indicate significance at the 1, 5, and 10% levels.