(1)

(2)

(3)

(4)

DDBTD

DDBTD

BTD

BTD

policy

−0.0314^***

−0.0307^***

−0.0102^***

−0.0098^***

(−7.67)

(−7.46)

(−3.50)

(−3.35)

lnlabor

−0.0032^***

-0.0032^***

−0.0008

−0.0007

(−4.31)

(−4.38)

(−1.49)

(−1.35)

labor

0.0000

0.0000^*

0.0000^***

0.0000^***

(1.40)

(1.71)

(2.61)

(2.67)

lnasset

0.0065^***

0.0066^***

0.0046^***

0.0047^***

(7.25)

(7.31)

(7.04)

(7.12)

asset

−0.0000^***

−0.0000^***

−0.0000^***

−0.0000^***

(−3.15)

(−3.08)

(−3.26)

(−3.11)

lev

0.0013^***

0.0014^***

0.0011^***

0.0011^***

(5.30)

(5.45)

(6.06)

(6.19)

npr

−0.0037

−0.0037

−0.0023

−0.0023

(−0.91)

(−0.90)

(−0.79)

(−0.78)

roa

0.1091^*

0.1085^*

0.0781^*

0.0775^*

(1.81)

(1.80)

(1.83)

(1.83)

growth

−0.0000^***

−0.0000^***

−0.0000^***

−0.0000^***

(−7.16)

(−7.45)

(−7.38)

(−7.16)

age

−0.0006

−0.0007^*

0.0006^*

0.0006^*

(−1.40)

(−1.68)

(1.88)

(1.79)

age₂

0.0000^*

0.0000^**

−0.0000

−0.0000

(1.96)

(2.04)

(−1.05)

(−1.16)

ppe

−0.0741^***

−0.0740^***

0.0005

0.0020

(−14.56)

(−14.36)

(0.13)

(0.53)

控制变量

Yes

Yes

Yes

Yes

年份固定效应

Yes

Yes

Yes

Yes

省份效应

No

Yes

No

Yes

行业效应

Yes

Yes

Yes

Yes

N

19,525

19,525

19,525

19,525

adj. R₂

0.120

0.123

0.091

0.094