TABLE 6.

Self-sampling test of a dynamic threshold effect.

Core explanatory variable	Model	Threshold value	Wald statistic	P-value	BS times	95% confidence interval
FDI	SYS-GMM	0.326	16.008***	0.000	1000	0.058	0.442
	DIF-GMM	0.085	55.380***	0.000	1000	0.058	0.442
OFDI	SYS-GMM	0.357	36.560***	0.000	1000	0.058	0.442
	DIF-GMM	0.430	222.818***	0.000	1000	0.058	0.442
Trade	SYS-GMM	0.442	118.123***	0.000	1000	0.058	0.442
	DIF-GMM	0.085	1.130***	0.000	1000	0.058	0.442

***Significant at the level of 1. P-value and critical value are obtained by repeated sampling of the GMM threshold panel regression program for 1,000 times. Wald statistic is used to judge whether the threshold feature is obvious. The smaller the corresponding probability, the more obvious the threshold feature is.