OP法

缩小时间窗口

安慰剂

(1)

(2)

(3)

(4)

(5)

(6)

DDD

−0.3189***

−0.3646***

−0.1365*

−0.1375**

0.0578

−0.0752

(0.0017)

(0.0003)

(0.0618)

(0.0307)

(0.6726)

(0.5074)

_cons

16.8360***

15.9040***

10.9446***

11.9315***

12.8234***

10.9733***

(0.0000)

(0.0000)

(0.0000)

(0.0000)

(0.0000)

(0.0000)

Control

No

Yes

Yes

Yes

No

Yes

Province

No

No

Yes

No

Yes

Yes

Industry

No

No

Yes

No

Yes

Yes

Stkcd

Yes

Yes

No

Yes

No

No

N

5854

5853

1598

1598

6384

6383

R²

0.8891

0.9001

0.5167

0.9495

0.3345

0.4974