Table 6 The robustness test of the cross terms of national level variable and trade cost density (general)

c _i  × T _t

−3.959***

−2.142***

−2.506***

−0.377

−3.372 ***

−3.622***

−2.229***

−0.951

(−8.09)

(−3.33)

(−2.94)

(−0.37)

(−6.77)

(−7.12)

(−3.31)

(−1.36)

c _i  × Justice Court _t

0.245***

(−3.89)

c _i  × Legal structure and Property rights _t

0.287***

(−3.99)

c _i  × Trade compliance costs _t

−0.203*

(−1.90)

c _i  × Tariff _t

0.574***

(−3.87)

c _i  × Control index _t

0.211***

(−4.1)

c _i  × Non-tariff barrier _t

0.114**

(−2.08)

c _i  × Total degree of freedom index _t

0.584***

(−3.45)

c _i  × ln(capital GDP) _t

0.346***

(−5.57)

Industrial fixed effect

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Time-fixed effect

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

R ²

0.6715

0.6727

0.6535

0.6713

0.6741

0.6547

0.6667

0.6935

Observation

238

238

238

238

238

238

238

238