对动态面板数据进行sargan检验,结果如下:
Sargan test of overid. restrictions: chi2(15) = 66.85 Prob > chi2 = 0.000
(Not robust, but not weakened by many instruments.)
Hansen test of overid. restrictions: chi2(15) = 44.15 Prob > chi2 = 0.000
(Robust, but weakened by many instruments.)
这是说明工具变量不是有效地吗?应该怎么解决?