(1)

(2)

(3)

(4)

(5)

(6)

lnpat

lnpat1

lnpat2

lnpat

lnpat1

lnpat2

Dige

0.964^***

1.119^***

0.595^***

0.573^***

0.577^***

0.377^**

(0.178)

(0.158)

(0.163)

(0.192)

(0.170)

(0.180)

lev

0.072

0.053

0.089

(0.157)

(0.136)

(0.113)

size

0.128^***

0.161^***

0.076^***

(0.029)

(0.025)

(0.027)

con

0.001

−0.000

0.002

(0.002)

(0.002)

(0.002)

age

−0.333^***

−0.242^***

−0.226^***

(0.025)

(0.015)

(0.024)

ROA

0.422^**

0.400^**

0.211

(0.199)

(0.178)

(0.152)

常数项

1.333

1.011

0.608

−0.547

−1.827

−0.484

(1.111)

(1.009)

(0.728)

(1.282)

(1.162)

(0.934)

公司/行业

是

是

是

是

是

是

观测值

14,610

14,610

14,610

14,610

14,610

14,610

r2

0.021

0.021

0.017

0.028

0.033

0.020