Table 3 Robustness test.

From: Digital economy and urban innovation level: A quasi-natural experiment from the strategy of “Digital China”

Variable

Panel 1: Consider sample selection and exclusion policies

Panel 2: Substitution of explanatory variables

Panel 3: Replacement of control variables

(1)

(2)

(3)

(4)

(5)

(6)

(7)

DID

2.199**

3.632***

3.686**

0.127***

0.043***

3.514***

1.382**

 

(0.903)

(1.061)

(1.739)

(0.044)

(0.006)

(0.738)

(0.790)

Control variable

YES

YES

YES

YES

YES

YES

YES

N

3024

2881

2552

3112

2552

3,123

2,552

R-squared

0.407

0.410

0.280

0.794

0.645

0.280

0.461

Urban Effect

YES

YES

YES

YES

YES

YES

YES

Time Effect

YES

YES

YES

YES

YES

YES

YES

  1. **, and *** indicate significance at the 10%, 5%, and 1% levels, respectively, with robustness standard errors in parentheses below.