求助

顶起来，望高手指点

怎么没有答复的

The Sargan-Hansen test is a test of overidentifying restrictions.  The joint null hypothesis is that the instruments are valid instruments, i.e., uncorrelated with the error term, and that the excluded instruments are correctly excluded from the estimated equation.
Hansen J 检验的原假设是你检验的工具变量中至少一个是有效的（与扰动项不相关），所以不拒绝原假设说明你的工具变量中至少有一个是有效的
详见help ivreg2##overidtests

请问题主，IV-GMM就是GMM吗？用的stata命令是什么呀